Thiophene-2,3-Dialdehyde Enables Chemoselective Cyclization on Unprotected Peptides, Proteins, and Phage Displayed Peptides

Ortho-phthalaldehyde has recently found wide potentials for protein bioconjugation and peptide cyclization. Herein, the second-generation dialdehyde-based peptide cyclization method is reported. The thiophene-2,3-dialdehyde (TDA) reacts specifically with the primary amine (from Lys side chain or peptide N-terminus) and thiol (from Cys side chain) within unprotected peptides to generate a highly stable thieno[2,3-c]pyrrole-bridged cyclic structure, while it does not react with primary amine alone. This reaction is carried out in the aqueous buffer and features tolerance of diverse functionalities, rapid and clean transformation, and operational simplicity. The features allow TDA to be used for protein stapling and phage displayed peptide cyclization.

[P2X7R promotes migration and invasion of Lewis lung cancer cells by activating the AKT signaling pathway]

OBJECTIVE

To explore the role of P2X7 receptor (P2X7R) in migration and invasion of mouse Lewis lung cancer (LLC) cells and examine the tumorigenic ability of LLC cells in P2X7R-knockout mice.

METHODS

RT-PCR was used to examine P2X7R mRNA expression in LLC cells. LLC cells were treated with ATP (as a P2X7R agonist) or 2'- 3'- O- (4-benzoyl- benzoyl)-ATP (BzATP) (a P2X7R agonist) with or without pretreatment with P2X7R antagonist oxATP or A438079. The changes in migration and invasive abilities of the cells were evaluated using wound healing assay and Transwell assay; Western blotting was performed to determine the activation level of the key proteins in the AKT signaling pathway. The effects of BzATP, A438079, and LY294002 (a inhibitor of the PI3K/AKT pathway) on migration and invasion of LLC cells were also examined. In wild-type (WT) and P2X7R knockout (P2X7^-/-) C57BL/6 mice, the growth of subcutaneous LLC cell xenografts were observed by measuring tumor volume and weight.

RESULTS

P2X7R expression was detected in LLC cells. Treatment with P2X7R agonist significantly enhanced migration and invasion abilities of LLC cells, and this effect was inhibited by application of P2X7R antagonists (P < 0.001). Western blotting showed that BzATP treatment of LLC cells significantly increased the expression level of p-AKT protein, which was obviously lowered by treatment with P2X7R antagonist (P < 0.01). P2X7R antagonist strongly inhibited BzATP-induced enhancement of LLC cell migration and invasion (P < 0.001). In the tumor- bearing mice, the tumor volume and weight were significantly lower in P2X7^-/- mice than in WT mice (P < 0.05).

CONCLUSION

P2X7R promotes migration and invasion of LLC cells by activating the AKT signaling pathway, and LLC cells show lowered tumorigenic capacity in P2X7^-/- mice.

Astrocytes and major depression: The purinergic avenue

Major depressive disorder (MDD) is one of the most prevalent psychiatric illnesses worldwide which impairs the social functioning of the afflicted patients. Astrocytes promote homeostasis of the CNS and provide defense against various types of harmful influences. Increasing evidence suggests that the number, morphology and function of astrocytes are deteriorated in the depressed brain and the malfunction of the astrocytic purinergic system appears to participate in the pathophysiology of MDD. Adenosine 5'-triphosphate (ATP) released from astrocytes modulates depressive-like behavior in animal models and probably also clinical depression in patients. Astrocytes possess purinergic receptors, such as adenosine A_2A receptors (Rs), and P2X7, P2Y₁, and P2Y₁₁Rs, which mediate neuroinflammation, neuro(glio)transmission, and synaptic plasticity in depression-relevant areas of the brain (e.g. medial prefrontal cortex, hippocampus, amygdala nuclei). By contrast, astrocytic A₁Rs are neuroprotective and immunosuppressive. In the present review, we shall discuss the release of purines from astrocytes, and the expression/function of astrocytic purinergic receptors. Subsequently, we shall review in more detail novel evidence indicating that the dysregulation of astrocytic purinergic signaling actively contributes to the pathophysiology of depression and shall discuss possible therapeutic options based on knowledge recently acquired in this field.

Fluid Shear Stress Promotes Osteoblast Proliferation and Suppresses Mitochondrial-Mediated Osteoblast Apoptosis Through the miR-214-3p-ATF4 Signaling Axis

MicroRNAs (miRNAs) play vital roles in bone metabolism and participate in the mechanically induced bone alterations. The underlying molecular mechanisms by which fluid shear stress (FSS) regulate the proliferative and apoptotic phenotypic changes of osteoblasts remain elusive. The study aimed to investigate the regulatory effects of FSS on osteoblast proliferative and apoptotic phenotypes and the roles of miR-214-3p-ATF4 (activating transcription factor 4) signaling axis in the mechanomodulation processes. FSS promoted the proliferative activity of osteoblasts and suppressed mitochondrial-mediated osteoblast apoptosis. FSS decreased miR-214-3p expression and increased ATF4 expression in MC3T3-E1 osteoblasts. MiR-214-3p inhibited osteoblast proliferative activity and promoted mitochondrial-mediated osteoblast apoptosis. Overexpression of miR-214-3p attenuated FSS-enhanced osteoblast proliferation and FSS-suppressed mitochondrial-mediated osteoblast apoptosis. We validated that ATF4 acted as a target gene of miR-214-3p. Moreover, miR-214 3p regulated osteoblast proliferation and apoptosis through targeting ATF4. Taken together, our study proved that FSS could suppress mitochondrial-mediated osteoblast apoptosis and promote osteoblast proliferation through the miR-214-3p-ATF4 signaling axis.

[Bioinformatic analysis of differentially expressed proteins in the dorsal raphe nucleus of rats after continuous treatment with olanzapine]

OBJECTIVE

To analyze the differentially expressed proteins in the dorsal raphe nucleus of rats treated with olanzapine and explore the possible mechanism of metabolic disorders in the early stage of olanzapine treatment.

METHODS

Twenty male and 20 female SD rats were both randomized equally into olanzapine group and control group for daily treatment with olanzapine and saline for 4 weeks, respectively. One hour after the last treatment, the dorsal raphe nucleus of the rats was dissected for proteomic analysis using iTRAQ combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). GO, KEGG pathway, COG, pathways and protein interaction network analyses of the differentially expressed proteins were performed. Several target genes were selected from the proteomic list, and their expression levels in the dorsal raphe nucleus of another 24 mice with identical grouping and treatment using real time real-time quantitative PCR and Western blotting.

RESULTS

A total of 214 differentially expressed proteins were identified in the dorsal raphe nucleus of olanzapine-treated mice, including 72 unregulated and 142 downregulated proteins. GO analyses showed that the differentially expressed proteins were enriched in cellular process, biological regulation, metabolic process, response to stimulus, multicellular organismal process, bindings, catalytic activity, molecular function regulator and transcription regulator activity. KEGG analysis suggested that these proteins were enriched in fluid shear stress and atherosclerosis, serotonergic synapse, butanoate metabolism, thyroid hormone synthesis and IL-17 signaling pathway. The differentially expressed proteins Cav1, Hsp90b1, Canx, Gnai1, MAPK9, and LOC685513 were located at the nodes of the protein-protein interaction network in close relation with metabolic disorders. In olanzapine-treated mice, the expression of Hmgcs2, a negative regulator of apoptosis, was significantly down-regulated in the dorsal raphe nucleus, where the expressions of Pla2g4e, Slc6a4 and Gnai1 involved in serotonergic synapse were significantly upregulated.

CONCLUSION

In the early stage of treatment, olanzapine may contribute to the occurrence of metabolic disorders in rats by regulating the expressions of Cav1, Hsp90b1, Canx, Gnai1, MAPK9, LOC685513 (Gng14) and 5-HTR2 synapse-related proteins in the dorsal raphe nucleus.

Susceptibility-weighted imaging cannot distinguish radionecrosis from recurrence in brain metastases after radiotherapy: a comparison with high-grade gliomas

AIM

To explore the efficiency of susceptibility-weighted imaging (SWI) in the differential diagnosis of recurrence from radionecrosis in brain metastases (BM) and in high-grade gliomas (HGG).

MATERIALS AND METHODS

From September 2016 to November 2018, 56 patients with BM and 42 patients with HGG were included in this retrospective study. BM and HGG were assigned to the recurrence and radionecrosis groups according to their histopathology or follow-up results. The proportion of dark signal intensity (proDSI), which was defined as the area of dark signal on SWI or the enhancing area on contrast-enhanced T1-weighted imaging (T1WI), was calculated for each patient. Analysis of variance (ANOVA) with Tukey's honestly significant difference test was used for the repeat multiple comparisons. Receiver operating characteristic curve analysis was performed to validate the diagnostic performance.

RESULTS

For HGG, the proDSI in the recurrence group was significantly lower than that in the radionecrosis group (0.13 ± 0.05 versus 0.43 ± 0.11, p<0.001); however, for BM, no statistical difference was found between groups (0.49 ± 0.09 versus 0.46 ± 0.08, p=0.26). proDSI had the best diagnostic performance (AUC = 0.87, 95% CI: 0.76-0.98; sensitivity = 0.87; specificity = 0.88) for HGG, when a cut-off value of 0.21 was selected.

CONCLUSIONS

Semi-quantitative analysis using SWI is feasible for the differential diagnosis between recurrence and radionecrosis in HGG, but is not feasible in BM. Semi-quantitative assessment based on SWI should interpreted with caution in BM after radiotherapy in clinical practice.

[Application of three-dimensional visualization technique in laparoscopic D3 radical resection of right colon cancer]

OBJECTIVE

To explore the clinical value of three-dimensional (3D) visualization technique in laparoscopic D3 radical resection of right colon cancer.

METHODS

We retrospectively analyzed the clinical data of 73 patients with right colon cancer undergoing laparoscopic D3 radical operation in our hospital between May, 2019 and March, 2021. Among these patients, 41 underwent enhanced CT examination with 3D visualization reconstruction to guide the actual operation, and 32 underwent enhanced CT examination only before the operation (control group). In 3D visualization group, we examined the coincidence rate between the 3D visualization model and the findings in surgical exploration of the anatomy and variations of the main blood vessels, supplying vessels of the tumor, and the tumor location, and the coincidence rate between the actual surgical plan for D3 radical resection of right colon cancer and the plan formulated based on the 3D model. The operative time, estimated blood loss, unexpected injury of blood vessels, number of harvested lymph nodes, mean time of the first flatus, complications, postoperative hospital stay and postoperative drainage volume were compared between the two groups.

RESULTS

The operative time was significantly shorter in 3D visualization group than in the control group (P < 0.05). The volume of blood loss, proportion of unexpected injury of blood vessel, the number of harvested lymph nodes, time of the first flatus, proportion of complications, postoperative hospital stay and postoperative drainage volume did not differ significantly between the two groups (P > 0.05). In the 3D visualization group, the 3D visualization model clearly displayed the shape and direction of the colon, the location of the tumor, the anatomy and variation of the main blood vessels and the blood vessels supplying the cancer, and showed a coincidence rate of 100% with the findings by surgical exploration. The surgical plan for D3 radical resection of right colon cancer was formulated based on the 3D model also showed a coincidence rate of 100% with the actual surgical plan.

CONCLUSION

The 3D visualization reconstruction technique allows clear visualization the supplying arteries of the tumor and their variations to improve the efficiency, safety and accuracy of laparoscopic D3 radical resection of right colon cancer.

[Comparison of the long-term outcomes of focused ultrasound ablation surgery for uterine fibroids and myomectomy]

Objective: To compare the long-term outcomes after focused ultrasound ablation surgery (FUAS) versus myomectomy for uterine fibroids. Methods: A retrospective study was conducted on women who were treated by FUAS or myomectomy for uterine fibroids at First Medical Center of Chinese PLA General Hospital from January 2007 to January 2015. Regular follow-up was conducted to evaluate the symptoms relief, symptoms recurrence, the need for re-interventions and complications of the two groups. Results: The effective rates were 95.7% (730/763) and 95.5% (1 151/1 205) in women who were treated by FUAS and myomectomy, no statistical difference was seen between the two groups (χ²=0.027, P=0.869). The cumulative rates of symptoms recurrence at 1 year, 3 years, 5 years, 8 years and 10 years of follow-up in FUAS group were 1.8%, 6.8%, 11.9%, 15.2% and 15.9%, respectively; and the cumulative re-intervention rates were 0.7%, 4.1%, 6.8%, 9.9% and 11.0%, respectively. The cumulative rates of symptoms recurrence at 1 year, 3 years, 5 years, 8 years and 10 years of follow-up in myomectomy group were 1.8%, 5.9%, 10.6%, 14.2% and 14.9%, respectively; and the cumulative re-intervention rates were 0.9%, 4.5%, 7.8%, 10.3% and 11.4%, respectively. No statistical differences were seen between the two groups (all P>0.05). There were no significant differences in the effective rate, symptoms recurrence rate and re-intervention rate between the two groups in patients with intermural fibroids; but the effective rate of FUAS (95.9%, 235/245) was higher than that of myomectomy (89.1%, 115/129), the symptoms recurrence rate (11.9%, 28/235) was lower than that of myomectomy (27.8%, 32/115), and the re-intervention rate (7.7%, 18/235) was lower than that of myomectomy (17.4%, 20/115) in patients with submucosal fibroids, there were significant different (all P<0.05). The effective rate of FUAS (91.0%, 132/145) was lower than that of myomectomy (97.0%, 322/332), the symptoms recurrence rate (32.6%, 43/132) was higher than that of myomectomy (9.9%, 32/322), and the re-intervention rate (22.0%, 29/132) was higher than that of myomectomy group (6.2%, 20/132) in patients with subserosal fibroids, there were significant different (all P<0.01). The incidences of total [1.8% (14/763) vs 21.9% (264/1 205)], minor and moderate adverse events were lower in FUAS group than myomectomy group (all P<0.001). Conclusion: Satisfaction with long-term outcomes after FUAS treatment or myomectomy for uterine fibroids is comparable.

[Progress on clinical trials of common gastrointestinal cancer drugs in China from 2012 to 2021]

Objective: Systematically summarize the research progress of clinical trials of gastric cancer oncology drugs and the overview of marketed drugs in China from 2012 to 2021, providing data and decision-making evidence for relevant departments. Methods: Based on the registration database of the drug clinical trial registration and information disclosure platform of Food and Drug Administration of China and the data query system of domestic and imported drugs, the information on gastric cancer drug clinical trials, investigational drugs and marketed drugs from January 1, 2012 to December 31, 2021 was analyzed, and the differences between Chinese and foreign enterprises in terms of trial scope, trial phase, treatment lines and drug type, effect and mechanism studies were compared. Results: A total of 114 drug clinical trials related to gastric tumor were registered in China from 2012 to 2021, accounting for 3.7% (114/3 041) of all anticancer drug clinical trials in the same period, the registration number showed a significant growth rate after 2016 and reached its peak with 32 trials in 2020. Among them, 85 (74.6%, 85/114) trials were initiated by Chinese pharmaceutical enterprise. Compared with foreign pharmaceutical enterprise, Chinese pharmaceutical enterprise had higher rates of phase I trials (35.3% vs 6.9%, P=0.001), but the rate of international multicenter trials (11.9% vs 67.9%, P<0.001) was relatively low. There were 76 different drugs involved in relevant clinical trials, of which 65 (85.5%) were targeted drugs. For targeted drugs, HER2 is the most common one (14 types), followed by PD-1 and multi-target VEGER. In the past ten years, 3 of 4 marketed drugs for gastric cancer treatment were domestic and included in the national medical insurance directory. Conclusions: From 2012 to 2021, China has made some progress in drug research and development for gastric carcinoma. However, compared with the serious disease burden, it is still insufficient. Targeted strengthening of research and development of investment in many aspects of gastric cancer drugs, such as new target discovery, matured target excavating, combination drug development and early line therapy promotion, is the key work in the future, especially for domestic companies.