Identification of YCH2823 as a novel USP7 inhibitor for cancer therapy.

Inhibition of the human ubiquitin-specific protease 7 (USP7), the key deubiquitylating enzyme in regulating p53 protein levels, has been considered an attractive anticancer strategy. In order to enhance the cellular activity of FT671, scaffold hopping strategy was employed. This endeavor resulted in the discovery of YCH2823, a novel and potent USP7 inhibitor.YCH2823 demonstrated remarkable efficacy in inhibiting the growth of a specific subset of TP53 wild-type, -mutant, and MYCN-amplified cell lines, surpassing the potency of FT671 by approximately 5-fold. The mechanism of action of YCH2823 involves direct interaction with the catalytic domain of USP7, thereby impeding the cleavage of ubiquitinated substrates. An increase in the expression of p53 and p21, accompanied by G1 phase arrest and apoptosis, was observed upon treatment with YCH2823. Subsequently, the knockdown of p53 or p21 in CHP-212 cells exhibited a substantial reduction in sensitivity to YCH2823, as evidenced by a considerable increase in IC50 values up to 690-fold. Furthermore, YCH2823 treatment specifically enhanced the transcriptional and protein levels of BCL6 in sensitive cells. Moreover, a synergistic effect between USP7 inhibitors and mTOR inhibitors was observed, suggesting the possibility of novel therapeutic strategies for cancer treatment. In conclusion, YCH2823 exhibits potential as an anticancer agent for the treatment of both TP53 wild-type and -mutant tumors.

SOMCL-19-133, a novel, selective, and orally available inhibitor of NEDD8-activating enzyme (NAE) for cancer therapy.

Inhibition of the NEDD8-activating enzyme (NAE), the key E1 enzyme in the neddylation cascade, has been considered an attractive anticancer strategy with the discovery of the first-in-class NAE inhibitor, MLN4924. In this study, we identified SOMCL-19-133 as a highly potent, selective, and orally available NAE inhibitor, which is an analog to AMP. It effectively inhibited NAE with an IC50 value of 0.36 nM and exhibited more than 2855-fold selectivity over the closely related Ubiquitin-activating enzyme (UAE). It is worth noting that treatment with SOMCL-19-133 prominently inhibited Cullin neddylation and delayed the turnover of a panel of Cullin-RING ligases (CRLs) substrates (e.g., Cdt1, p21, p27, and Wee1) at lower effective concentrations than that of MLN4924, subsequently caused DNA damage and Chk1/Chk2 activation, and thus triggered cell cycle arrest and apoptosis. Moreover, SOMCL-19-133 exhibited potent antiproliferative activity against a broad range of human tumor cell lines (mean IC50 201.11 nM), which was about 5.31-fold more potent than that of MLN4924. In vivo, oral delivery treatments with SOMCL-19-133, as well as the subcutaneous injection, led to significant tumor regression in mouse xenograft models. All of the treatments were well tolerated on a continuous daily dosing schedule. Compared with MLN4924, SOMCL-19-133 had a 5-fold higher peak plasma concentration, lower plasma clearance, and a 4-fold larger area under the curve (AUClast). In conclusion, SOMCL-19-133 is a promising preclinical candidate for treating cancers owing to its profound in vitro and in vivo efficacy and favorable pharmacokinetic properties.

Design, synthesis and pharmacological evaluation of new PARP1 inhibitors by merging pharmacophores of olaparib and the natural product alantolactone.

Based on the reported synthetic lethality of the combination of PARP inhibitor olaparib with the natural product alantolactone, we designed several series of new PARP1 inhibitors by structurally merging both compounds into a single hybrid compound. Among them, compounds 20e and 25a displayed not only high biochemical activity (IC50 = 2.99 nM and 5.91 nM vs 11.36 nM), but also higher inhibitory effects against proliferation of BRCA1-deficient UWB1.289 cells than olaparib (IC50 = 0.27 µM and 0.41 µM vs 0.66 µM). Much weak activity was observed in BRCA1 wild-type human fetal lung IMR-90 and WI-38 cells (IC50s > 10 µM). Treatment with compounds 20e and 25a was found to induce increased levels of γH2AX in a concentration-dependent manner in both MDA-MB-436 and Capan-1 cells to a degree comparable with that of olaparib. Further mechanism study indicated that these compounds activated the cell cycle checkpoints, and subsequently induced G2/M arrest and apoptosis. The results validated that merging PARP inhibitors with other DNA-damage related compounds would produce more potent PARP inhibitors for anticancer studies. However, the poor aqueous solubility and low cell penetration of the current hybrid compounds call for further structural optimization.

[Closed reduction and three Kirschner pin fixation at the radial side for the treatment of supracondylar fracture in children with Gartland type II and type III].

OBJECTIVE: To investigate the characteristics of supracondylar fracture of humerus in children and to explore the effect of closed reduction and internal fixation at radial side on the fracture. METHODS: The children with fractures of Gartland type II and type III in our hospital from June 2010 to June 2013 were reviewed. There were 28 males and 7 females, ranging in age from 1 year and 1 month to 2 years and 6 months, with an average of 2 years and 1 month. According to Gartland classification, 19 cases were type II, 16 cases were type III. There were 3 patients with radial nerve injuries, and 5 patients with anterior interosseous nerve injuries. There were no vascular injuries. All the patients were treated with closed reduction and three Kirschner fixation at the radial side, followed by the plaster external fixation with elbowed flexion at 90 °. The X-ray examination was performed at the second day after operation. The joint function exercise began about at 2 to 3 weeks after operation when the plaster fixation was removed, and opportune time for removal of Kirschners depends on the situation of fracture healing. The operation time, nerve recovery, and the elbow joint function were observed. RESULTS: All the children were followed up, and all the fractures had bony union. According to Flynn score system at the final follow-up, 28 patients got an excellent result, 4 good, 1 poor and 2 bad. CONCLUSION: Three Kirschner fixation at the radial side for the treatment of supracondylar fracture of humerus has advantages of minimally invasive, shorter time of hospitalization, simple removal of the internal fixation and reliable therapeutic effects.

[Detection of antibodies to cyclic citrullinated peptides and its clinical significance in patients with chronic hepatitis B virus infection].

OBJECTIVE: To detect the presence of antibodies to cyclic citrullinated peptides (anti-CCP) in patients with chronic hepatitis B virus (HBV) infection and evaluate its potential clinical significance. METHODS: Serum samples of 280 patients with chronic HBV infection and 40 healthy controls were collected from May 2011 to October 2011 and tested for anti-CCP and IgM-rheumatoid factor (RF). Anti-CCP was detected by ELISA and RF by immunonephelometry. All of 280 patients with chronic HBV infection were divided into 3 groups according to joint symptoms: asymptomatic group, HBV-associated arthropathy group and HBV concomitant RA group. Meanwhile, according to liver disease, they were divided into 3 groups: carrier group, chronic hepatitis group and cirrhosis group. RESULTS: The positive rates of anti-CCP and RF were 5.7% and 13.9% in patients with chronic HBV infection respectively. Anti-CCP was detected in 3 of 265 non-RA (1.1%) and 13 of 15 RA patients (86.7%). And RF were detected in 27 of 265 non-RA (10.2%) and 12 of 15 RA patients (80.0%). Twelve of 15 RA patients were positive for both anti-CCP and RF. The specificity of anti-CCP for RA was 98.9% in chronic HBV infection while the specificity of RF 89.8% (P < 0.01). Compared with the positive detection rates of anti-CCP and RF among liver disease subgroups, no significant difference existed between the subgroups. The levels of anti-CCP and RF in HBV concomitant RA group were statistically higher than those in asymptomatic group, HBV-associated arthropathy group and healthy controls (all P < 0.01). The level of RF in patients with HBV-associated arthropathy group was higher than that in asymptomatic group (U = 6017, P < 0.05). CONCLUSION: It is better to detect anti-CCP than RF to discriminate non-RA from concomitant RA in patients with chronic HBV infection.

Effects of dendritic cells transfected with full-length wild-type p53 and stimulated by gastric cancer lysates on immune response.

AIM: To investigate the effects of dendritic cells (DCs) transfected with full-length wild-type p53 and stimulated by gastric cancer lysates on immune response. METHODS: The wild-type p53 was transduced to DCs with adenovirus, and the DCs were stimulated by gastric cancer lysates. The surface molecules (B7-1, B7-2, MHC-I, MHC-II) of all DCs were detected by FACS, and the ability of the DCs to induce efficient and specific immunological response in anti-51Cr-labeled target cells was studied. BALB/c mice injected with DCs and Mk28 were established, and CTL response in mice immunized with Lywt-p53DC was evaluated. Tumor-bearing mice were treated with Lywt-p53DC. RESULTS: The surface molecules of Lywt-p53DC had a high expression of B7-1 (86.70 +/- 0.07%), B7-2 (18.77 +/- 0.08%), MHC-I (87.20 +/- 0.05%) and MHC-II (56.70 +/- 0.07%); T lymphocytes had a specific CTL lysis ability induced by Lywt-p53DC; the CTL lysis rate was as high as 81%. The immune protection of Lywtp-53DC was obvious, the tumor diameter in Lywtp-53DC group was 3.10 +/- 0.31 mm, 2.73 +/- 0.23 mm, 3.70 +/- 0.07 mm on d 13, 16 and 19, respectively, which were smaller than control, DC, wtp53DC and LyDC group (P<0.05). Tumor growth rate in Lywtp53DC group was slower than that in other groups (P<0.05). CONCLUSION: DCs transfected with wild-type p53 and stimulated by gastric cancer lysates have specific CTL killing activity.