Optimizations of an ELISA-like high-throughput screening assay for the discovery of β-catenin/TCF4 interaction antagonists / 生物工程学报

In canonical Wnt/β-catenin signaling pathway, β-catenin/TCF4 (T-cell factor 4) interaction plays an important role in the pathogenesis and development of non-small cell lung cancer (NSCLC), and it is tightly associated with the proliferation, chemoresistance, recurrence and metastasis of NSCLC. Therefore, suppressing β-catenin/TCF4 interaction in Wnt/β-catenin signaling pathway would be a new therapeutic avenue against NSCLC metastasis. In this study, considering the principle of enzyme-linked immunosorbent assay (ELISA), an optimized high-throughput screening (HTS) assay was developed for the discovery of β-catenin/TCF4 interaction antagonists. Subsequently, this ELISA-like screening assay was performed using 2 μg/mL GST-TCF4 βBD and 0.5 μg/mL β-catenin, then a high Z' factor of 0.83 was achieved. A pilot screening of a natural product library using this ELISA-like screening assay identified plumbagin as a potential β-catenin/TCF4 interaction antagonist. Plumbagin remarkably inhibited the proliferation of A549, H1299, MCF7 and SW480 cell lines. More importantly, plumbagin significantly suppressed the β-catenin-responsive transcription in TOPFlash assay. In short, this newly developed ELISA-like screening assay will be vital for the rapid screening of novel Wnt inhibitors targeting β-catenin/TCF4 interaction, and this interaction is a potential anticancer target of plumbagin in vitro.

Selection of surgical methods for different sites of symptomatic Rathke's cleft cyst and clinical efficacies of these patients / 中华神经医学杂志

Objective:To explore the selection of surgical methods for different sites of symptomatic Rathke's cleft cyst (RCC) and the clinical efficacies of these patients.Methods:Forty-seven patients with symptomatic RCC, admitted to our hospital from January 2016 to December 2019, were chosen in our study; 21 patients with intrasellar symptomatic RCC accepted surgery via unilateral nasal approach at the right side, 19 patients with intra-suprasellar symptomatic RCC accepted surgery via bilateral nasal approach, 3 patients with suprasellar symptomatic RCC accepted endonasal transsphenoidal surgery under endoscope, and 4 patients with suprasellar symptomatic RCC accepted craniotomy via pterion approach. The clinical efficacies and complications of patients accepted different surgical methods were compared. All patients were followed up for 3-36 months to observe the recurrence.Results:The postoperative symptoms of the patients were effectively improved, including headache relief ratio of 27/31, vision loss improvement ratio of 5/5, high prolactin relief ratio of 11/13, pituitary function improvement ratio of 9/18. Complications occurred in 6 patients, presenting as diabetes insipidus. Four patients recurred during follow-up.Conclusion:Intrasellar and intra-suprasellar symptomatic RCC accepted surgery via endoscopic transnasal transsphenoidal approach are safe and effective; selection of surgical methods for suprasellar symptomatic RCC should be determined according to the sizes and growth directions of cysts.

Optimization of expression conditions and determination the proteolytic activity of codon-optimized SARS-CoV-2 main protease in Escherichia coli / 生物工程学报

The main protease (Mpro) of SARS-CoV-2 is a highly conserved and mutation-resistant coronaviral enzyme, which plays a pivotal role in viral replication, making it an ideal target for the development of novel broad-spectrum anti-coronaviral drugs. In this study, a codon-optimized Mpro gene was cloned into pET-21a and pET-28a expression vectors. The recombinant plasmids were transformed into E. coli Rosetta(DE3) competent cells and the expression conditions were optimized. The highly expressed recombinant proteins, Mpro and Mpro-28, were purified by HisTrapTM chelating column and its proteolytic activity was determined by a fluorescence resonance energy transfer (FRET) assay. The FRET assay showed that Mpro exhibits a desirable proteolytic activity (25 000 U/mg), with Km and kcat values of 11.68 μmol/L and 0.037/s, respectively. The specific activity of Mpro is 25 times that of Mpro-28, a fusion protein carrying a polyhistidine tag at the N and C termini, indicating additional residues at the N terminus of Mpro, but not at the C terminus, are detrimental to its proteolytic activity. The preparation of active SARS-CoV-2 Mpro through codon-optimization strategy might facilitate the development of the rapid screening assays for the discovery of broad-spectrum anti-coronaviral drugs targeting Mpro.

Mining Polo-Box domain of Polo-like kinase 1 as a new therapeutic target for cancer / 生物工程学报

Polo-like kinase 1 (Plk1) is widely regarded as one of the most promising targets for cancer therapy due to its essential role in cell division and tumor cell survival. At present, most Plk1 inhibitors have been developed based on kinase domain, some of which are in clinical trial. However, inhibitors targeting kinase domain face off-target effect and drug resistance owing to the conserved nature and the frequent mutations in the ATP-binding pocket. In addition to a highly conserved kinase domain, Plk1 also contains a unique Polo-Box domain (PBD), which is essential for Plk1's subcellular localization and mitotic functions. Inhibitors targeting Plk1 PBD show stronger selectivity and less drug resistance for cancer therapy. Therefore, Plk1 PBD is an attractive target for the development of anti-cancer agents. In this review, we will summarize the up-to date drug discovery for targeting Plk1 PBD, including the molecular structure and cellular functions of Plk1 PBD. Small-molecule inhibitors targeting Plk1 PBD not only provide an opportunity to specifically inhibit Plk1 activity for cancer treatment, but also unveil novel biological basis regarding the molecular recognition of Plk1 and its substrates.

Intraoperative CT in endoscopic endonasal surgery for pituitary adenomas / 中华神经医学杂志

Objective To explore the value ofintraoperative CT (iCT) in endoscopic endonasal surgery for pituitary adenomas.Methods A retrospective analysis was conducted in the clinical data of 37 patients with pituitary adenomas performed endoscopic endonasal surgery with assistance of iCT in our hospital from November 2012 to June 2013.The influences of iCT on surgical process and results were analyzed.Results Intraoperative scanning was performed 1 to 3 times in each patient,averaging 1.43 times.The scanning time was only 50-60 s.Among the 37 patients,iCT revealed residual tumor in 11,9 of which underwent further resection with total removal in 6 and subtotal in 3,and the tumors in the other two patients were unable to be resected because the adenomas were tenacious and adhered closely to the internal carotid artery.Finally,the rate of gross total removal increased from 70.3％ to 86.5％,rising by 16.2％.No iCT related complications and severe surgical complication occurred.Conclusion The application of iCT in endoscopic endonasal surgery for pituitary adenomas provides objective evidence for the guidance of surgical procedure and real-time judgment of surgical results,which not only leads to higher percentage of tumor removal but also eliminates the unnecessary blind surgical manipulation to increase the safety of the operation.