Potent bromodomain and extraterminal domain inhibitor JAB-8263 suppresses MYC expression and exerts anti-tumor activity in colorectal cancer models

BACKGROUND

The overexpression of the MYC gene plays an important role in the occurrence, development and evolution of colorectal cancer (CRC). Bromodomain and extraterminal domain (BET) inhibitors can decrease the function BET by recognizing acetylated lysine residues, thereby downregulating the expression of MYC.

AIM

To investigate the inhibitory effect and mechanism of a BET inhibitor on CRC cells.

METHODS

The effect of the BET inhibitor JAB-8263 on the proliferation of various CRC cell lines was studied by CellTiter-Glo method and colony formation assay. The effect of JAB-8263 on the cell cycle and apoptosis of CRC cells was studied by propidium iodide staining and Annexin V/propidium iodide flow assay, respectively. The effect of JAB-8263 on the expression of c-MYC, p21 and p16 in CRC cells was detected by western blotting assay. The anti-tumor effect of JAB-8263 on CRC cells in vivo and evaluation of the safety of the compound was predicted by constructing a CRC cell animal tumor model.

RESULTS

JAB-8263 dose-dependently suppressed CRC cell proliferation and colony formation in vitro. The MYC signaling pathway was dose-dependently inhibited by JAB-8263 in human CRC cell lines. JAB-8263 dose-dependently induced cell cycle arrest and apoptosis in the MC38 cell line. SW837 xenograft model was treated with JAB-8263 (0.3 mg/kg for 29 d), and the average tumor volume was significantly decreased compared to the vehicle control group (P < 0.001). The MC38 syngeneic murine model was treated with JAB-8263 (0.2 mg/kg for 29 d), and the average tumor volume was significantly decreased compared to the vehicle control group (P = 0.003).

CONCLUSION

BET could be a potential effective drug target for suppressing CRC growth, and the BET inhibitor JAB-8263 can effectively suppress c-MYC expression and exert anti-tumor activity in CRC models.

Magnonic Unidirectional Spin Hall Magnetoresistance in a Heavy-Metal-Ferromagnetic-Insulator Bilayer

We report the observation of the unidirectional spin Hall magnetoresistance (USMR), which depends on the current or magnetization direction, in heavy-metal-ferromagnetic-insulator bilayer, Pt-Y_{3}Fe_{5}O_{12} (YIG). This USMR is apparently not caused by the mechanisms established in metallic bilayer, in which the ferromagnetic layer is required to be electrically conductive. From the magnetic field, current, temperature, and YIG thickness dependent measurements, the USMR is attributed to the asymmetric magnon creation and annihilation induced by the spin-orbit torque. This asymmetry and the resultant USMR are further revealed by the micromagnetic simulations combined with the spin-orbit torque and the spin drift-diffusion model. Our finding exhibits a nonlinear manipulation of magnons with the charge current.

The impact of COVID-19 on gastric cancer surgery: a single-center retrospective study

Background

The coronavirus disease 2019 (COVID-19) has been declared a global pandemic by the World Health Organization. Patients with cancer are more likely to incur poor clinical outcomes. Due to the prevailing pandemic, we propose some surgical strategies for gastric cancer patients.

Methods

The ‘COVID-19’ period was defined as occurring between 2020 and 01-20 and 2020-03-20. The enrolled patients were divided into two groups, pre-COVID-19 group (PCG) and COVID-19 group (CG). A total of 109 patients with gastric cancer were enrolled in this study.

Results

The waiting time before admission increased by 4 days in the CG (PCG: 4.5 [IQR: 2, 7.8] vs. CG: 8.0 [IQR: 2,20]; p = 0.006). More patients had performed chest CT scans besides abdominal CT before admission during the COVID-19 period (PCG: 22 [32%] vs. CG: 30 [73%], p = 0.001). After admission during the COVID period, the waiting time before surgery was longer (PCG: 3[IQR: 2,5] vs. CG: 7[IQR: 5,9]; p < 0.001), more laparoscopic surgeries were performed (PCG: 51[75%] vs. CG: 38[92%], p = 0.021), and hospital stay period after surgery was longer (7[IQR: 6,8] vs.9[IQR:7,11]; p < 0.001). In addition, the total cost of hospitalization increased during this period, (PCG: 9.22[IQR:7.82,10.97] vs. CG: 10.42[IQR:8.99,12.57]; p = 0.006).

Conclusion

This study provides an opportunity for our surgical colleagues to reflect on their own services and any contingency plans they may have to tackle the COVID-19 crisis.

Direct visualization of the novel pathogen, Spiroplasma eriocheiris, in the freshwater crayfish Procambarus clarkii (Girard) using fluorescence in situ hybridization

Spiroplasma eriocheiris is the first spiroplasma strain known to be pathogenic to freshwater crustaceans. It has caused considerable economic losses both in the freshwater crayfish Procambarus clarkii (Girard) and in some other crustaceans. The monitoring of the pathogen in crustacean populations and study of its behaviour in the laboratory require the development of reliable diagnostic tools. In this article, we improved microscopic identification of S. eriocheiris by combining in situ hybridization with specific fluorescently labelled oligonucleotide probes. The established fluorescence in situ hybridization (FISH) allowed simultaneous visualization, identification and localization of S. eriocheiris in the tissues of diseased crayfish P. clarkii and exhibited low background autofluorescence and ideal signal-to-noise ratio. With the advantages of better tissue penetration, potentially more specific and stable, we designed three species-specific oligonucleotide probes utilizing the sequences of 16S-23S rRNA intergenic spacer regions (ISRs) of S. eriocheiris. Positive hybridization signals were visualized in haemocytes and connective tissues of hepatopancreas, cardiac muscle and gill from diseased crayfish. This unique distribution pattern matched the pathological changes when diagnosed by H&E staining and indicated that S. eriocheiris probably spread throughout the tissues in P. clarkii by hemokinesis. This assay will facilitate our understanding of the pathogenesis of S. eriocheiris and enhance the early diagnosis of the novel pathogen.

RNF43 Inhibits Cancer Cell Proliferation and Could be a Potential Prognostic Factor for Human Gastric Carcinoma

Background/Aims: RNF43 is a member of transmembrane E3 ubiquitin ligases and plays important roles in tumor formation progression. In current study, we aimed to explore RNF43 expression and analyze its role in gastric carcinoma. Methods and Results: The level of RNF43 was detected in 77 cases of gastric carcinoma and matched normal tissues by real-time PCR, western blotting and immunohistochemistry. We found that the expression of RNF43 was significantly down-regulated in the gastric carcinoma tissues compared to the normal mucosae (all P<0.001). In addition, RNF43 was significantly correlated with histological differentiation (P = 0.001), T-stage cancer (P<0.001), depth of invasion (P<0.001), metastasis of regional lymph nodes (P<0.001), pTNM stage (P<0.001) and survival (P = 0.021). We further explored the biological functions of RNF43 in gastric carcinoma cell lines. Both gain- and loss-function assays show that RNF43 could suppress cell proliferation while promotes cell apoptosis. Further, we found that RNF43 was positively correlated with p53 and cleaved-caspase3 and negatively correlated with Ki67 and Lgr5. Concolusion: In conclusion, RNF43 might act as a tumor suppressor in gastric carcinoma and might be a potential indicator for the clinical assessment of gastric cancer prognosis

[Diagnosis and surgical therapy of primary retroperitoneal neurogenic tumors]

OBJECTIVE

To explore the diagnosis and surgical therapy for retroperitoneal neurogenic tumors (PRNTs).

METHODS

The clinical records of 79 surgically treated patients with retroperitoneal neurogenic tumor were retrospectively analyzed.

RESULTS

Twenty-nine patients presented with abdominal pain, 26 with abdominal mass, 15 with inferior extremities pain and numbness and 9 patients without clinical symptoms. Type B ultrasound (BUS), CT scan and surgical resection were performed for all the patients. Pathological analysis identified 19 patients with neurofibroma, 8 with neurilemmoma, 4 with paraganglioma, 21 with neurofibrosarcoma, 14 with malignant neurilemmoma, 6 with malignant paraganglioma, 5 with neuroectodermal tumor and 2 with neuroblastoma. The mortality rate of PRNT operation is was 1.3%, 3-year recurrence rate of benign tumor 0%, 5-year recurrence rate of benign tumor 12.9%, reoperation rate 100%, 5-year survival rate 100%. 3 years recurrence rate of malignancy tumor 41.6%, reoperation rate 90%, 5 years recurrence rate of malignancy tumor 79.1% and 5 years survival rate is 62.5%.

CONCLUSION

BUS, CT and MRI are decisive for localization diagnosis. Surgical resection is the mainstay of therapy for this disease. Pre-operative preparation of intestinal tract and blood, maintaining the intactness of involved nerve are important for tumor resection. To prevent tumor recurrence, the key surgical techniques are to minimize tumor residues and . to handle intervertebral foramen properly.

Structure-efficacy relationships of immunostimulatory activity of CpG-containing oligodeoxynucleotides on mouse spleen cells

AIM

To study the relationship between primary structures of oligodeoxynucleotides (ODN) containing unmethylated deoxycytidyldeoxyguanosine (CpG) dinucleotide motifs and their immunostimulatory activities in mouse spleen cells.

METHODS

A series of CpG ODN with different primary structures were synthesized. Their capabilities to stimulate mouse spleen cell proliferation were determined by [3H]thymidine incorporation assay. Cytokine (interleukin [IL]-6, IL-12, and IFN-alpha) secretion spectra induced by CpG ODN were assessed by ELISA. The ability of CpG ODN to activate natural killer cells was evaluated by standard 4 h (51)Cr-release assay. Flow cytometry was utilized to examine the expressions of various lymphocyte surface molecules on diverse immunocytes. An effective CpG ODN for murine, ODN1826, was set as the template of modification and the positive control.

RESULTS

The immunostimulatory activities of CpG ODN with different sequences and compositions varied markedly, both in character and in extent. It was useless for improving the immunostimulatory activity of ODN1826 by simply increasing the functional hexameric CpG motif number, modifying the site of CpG motifs, or changing the distance between multi-CpG motifs. However, an addition of a self-complementary palindrome structure at the 3'-end, but not the 5'-end of CpG ODN, aroused marked improvement in its activity. Several designed ODN had superior comprehensive immunostimulatory properties compared to ODN1826.

CONCLUSION

The immunostimulatory activity of a CpG ODN was relevant to its primary structure. It was useless for promoting immunostimulatory activity to simply change CpG motif number, space, or distance. The 3'-end palindrome structure of CpG ODN is associated with enhanced immunostimulatory activity.

Classification and pathophysiological mechanism of adult constipation caused by spastic pelvic floor syndrome in adults

AIM: To discuss the classification and pathophysiological mechanism of constipation caused by spastic pelvic floor syndrome (SPFS) in adults, and to investigate the mechanism of biofeedback training in treating this type of constipation.

METHODS: Biofeedback training was performed on 18 adult patients suffered from SPFS-caused constipation using the instruments produced by Medtronic Company with the basic circuit voltage of 1.53 μV for about 20-minute relaxation exercises. The basic resting and stimulated voltages of external anal sphincter (EAS) were obtained by the anal electrode, and then compared using statistical analysis.

RESULTS: Based on the resting voltage and the voltage change of EAS during simulation, the SPFS-caused constipation was classified into 3 types: type Ⅰ was characterized with a high resting voltage and paradoxical activity of EAS (44.44%); type Ⅱ was characterized with a high resting voltage of EAS (33.33%); type Ⅲ was characterized with paradoxical activity of EAS (22.22%). The patients with high resting voltages covered a percentage of 77.77%. There existed significant differences among three types (P = 0.001).

CONCLUSION: High resting voltages and secondary paradoxical activity may be the mechanisms of SPFS-caused constipation. A significant decrease of resting voltage and inhibition of EAS paradoxical activity can be obtained through biofeedback training.

[Study on the genetic variations of the major neutralization antigen VP7 of group A rotavirus type G1 in China]

OBJECTIVE

To study the genetic variations of the major neutralization antigen VP7 of group A rotavirus, type G1 in China.

METHODS

Twenty-three isolates derived from seven cities (Beijing, Shenyang, Xinxiang, Shanghai, Shenzhen, Guangzhou and Chongqing) during the period of 1988-1998 were analyzed for the VP7 cDNA sequences.

RESULTS

An obvious homology was observed in amino acid sequences of VP7 in the 23 isolates. Compared with the standard strain Wa, the variations were found at the position of aa 41, 49, 57, 65, 68, 74, 94, 97, 147, 170, 217, 218, 268, 281 and 291, respectively, and all of these were located in the variable region(VR)3,4,5,7,8 as well as in the C-terminal of the peptide. There seemed to be no remarkable divergence among the samples collected from different cities and all of them shared the same genetic lineage with the strain Jpn-417, though there might be one or two amino acid substitutions as time passed. When detected simultaneously with ELISA using G1 serotype-specific monoclonal antibody, the location of amino acid 91 was found presumably related to the neutralization epitope in VP7 of the type G1. Variations at some position may be resulted in the change of electropherotype.

CONCLUSIONS

The results indicated that the recent isolates with representative genetic and antigenic features should be used to develop effective vaccines, and the antigenic variations should be monitored periodically.

[The detection of pediatric mycoplasma pneumonia cases by polymerase chain reaction and it's clinical significance]

Mycoplasma DNA in nasopharynx secretion from seventy pediatric mycoplasma cases was detected, using rapid feit of PCR DNA sample preparation method and simple PCR processes. The result of PCR showed that: fifty-three positive cases with a positive rate 75.7%, comparing with only 53.8% positive rate using mycoplasma culture method (P < 0.05). Thirteen PCR positive patients were treated by Venoclysis Erythromycin for 10-14 days but mycoplasma DNA was identified by PCR again. Among them, eight cases turned negative, but five cases still remained positive. The resalt showed that this method was not only more sensitive and reliable than conventional culture techniques, but also could simplify the PCR processes. It could be used for routine mycoplasma pneumonia test and for early diagnosis, which leads to early treatment and evaluation of therapeufic effect.

[Diagnosis of endomyocardial fibrosis with endomyocardial biopsy]

Ten cases of endomyocardial fibrosis (EMF) were diagnosed with angiocardiography in showing a huge right atrium' tricuspid regurgitation and obliteration of right ventricular apex. The diagnosis was confirmed in 9 of them pathologically after right ventricular endomyocardial biopsy (EMB) in showing striking thickening of endocardium with presence of fibrosis. The remaining case was not confirmed with EMB. It is concluded that EMB is a quite useful method in the diagnosis of EMF. The cause of misdiagnosis in the tenth case was discussed.

Cloning and restriction mapping of human HBV genome serotype adr

A Bam HI cleaved 3.2 Kb fragment from the HBV adr genome was cloned in E. coli using pBR322 as vector. Sixteen restriction sites from the action of Bam HI, Hind III, Bgl I, Bgl II, Ava I, Hinc II, Sph I, Xba I, Xho I and Sst II were determined and mapped. No cleavage sites were found for Eco RI, Pst I, Sma I, Hpa I, Kpn I, Pvu II and Sst I. The restriction map for HBV adr is significantly different from those reported for the subtypes adw, ayw and adyw.