A novel small-molecule antagonist enhances the sensitivity of osteosarcoma to cabozantinib in vitro and in vivo by targeting DNMT-1 correlated with disease severity in human patients.

Advanced osteosarcoma (OSA) is highly aggressive and can lead to distant metastasis or recurrence. Here, a novel small-molecule inhibitor/antagonist of DNA methyltransferase 1 (DNMT-1) named DI-1 (inhibitor of DNMT-1) was explored to enhance the antitumor effect of a molecular-targeted agent, cabozantinib, on OSA cell lines. In patients with OSA, expression of DNMT-1 was negatively related with that of microRNA (miR)-34a and associated with a poor prognosis. In OSA cell lines (OSA cell line U2OS and an OSA cell line U2OSR resistance to cabozantinib), DI-1 treatment enhanced miR-34a expression by inhibiting hypermethylation of the promoter region of miR-34a mediated by DNMT-1. DI-1 enhanced the sensitivity of OSA cells (U2OS, 143B and MG63) to cabozantinib and other molecular-targeted agents by enhancing miR-34a expression and repressing activation of the Notch pathway. Mechanistically, DI-1 repressed recruitment of DNMT-1 to the promoter region of miR-34a and, in turn, decreased the methylation rate in the promoter region of miR-34a in OSA cells. These results suggest that repressing DNMT-1 activation by DI-1 enhances miR-34a expression in OSA cells and could be a promising therapeutic strategy for OSA.

[The effect of the sequence of intermediate instrumentation and distraction-reduction of the fractured vertebrae on the surgical treatment of mild to moderate thoracolumbar burst fractures].

Objective: To investigate the effect of the sequence of intermediate instrumentation with long screws and distraction-reduction on mild to moderate thoracolumbar fractures treated by posterior open and short-segmental fixation. Methods: The clinical data of 68 patients with mild to moderate thoracolumbar burst fractures who met the selection criteria between January 2016 and June 2019 were retrospectively analyzed. The patients were divided into group ISDRF (intermediate screws then distraction-reduction fixation, 32 cases) and group DRISF (distraction-reduction then intermediate screws fixation, 36 cases) according to the different operation methods. There was no significant difference between the two groups in age, gender, body mass index, fracture segment, cause of injury, and preoperative load-sharing classification score, thoracolumbar injury classification and severity score, vertebral canal occupational rate, back pain visual analogue scale (VAS) score, anterior height of fractured vertebra, and Cobb angle ( P>0.05). The operation time, intraoperative blood loss, complications, and fracture healing time were recorded and compared between the two groups. The vertebral canal occupational rate, anterior height of fractured vertebra, kyphosis Cobb angle, and back pain VAS score before and after operation were used to evaluate the effectiveness. Results: There was no significant difference in intraoperative blood loss and operation time between the two groups ( P>0.05). No vascular or spinal nerve injury and deep infections or skin infections occurred in both groups. At 1 week after operation, the vertebral canal occupational rate in the two groups was significantly improved when compared with that before operation ( P<0.05), no significant difference was found in the difference of vertebral canal occupational rate before and after operation and improvement between the two groups ( P>0.05). The patients in both groups were followed up 18-24 months, with an average of 22.3 months. All vertebral fractures reached bone union at 6 months postoperatively. At last follow-up, there was no internal fixation failures such as broken screws, broken rods or loose screws, but there were 2 cases of mild back pain in the ISDRF group. The intra-group comparison showed that the back pain VAS score, the anterior height of fractured vertebra, and the Cobb angle of the two groups were significantly improved at each time point postoperatively ( P<0.05); the VAS scores at 12 months postoperatively and last follow-up were also improved when compared with that at 1 week postoperatively ( P<0.05). At last follow-up, the anterior height of fractured vertebra in the ISDRF group was significantly lost when compared with that at 1 week and 12 months postoperatively ( P<0.05), the Cobb angle had a significant loss when compared with that at 1 week postoperatively ( P<0.05); the anterior height of fractured vertebra and Cobb angle in DRISF group were not significantly lost when compared with that at 1 week and 12 months postoperatively ( P>0.05). The comparison between groups showed that there was no significant difference in the remission rate of VAS score between the two groups at 1 week postoperatively ( P>0.05), the recovery value of the anterior height of fractured vertebra in ISDRF group was significantly higher than that in DRISF group ( P<0.05), the loss rate at last follow-up was also significantly higher ( P<0.05); the correction rate of Cobb angle in ISDRF group was significantly higher than that in DRISF group at 1 week postoperatively ( P<0.05), but there was no significant difference in the loss rate of Cobb angle between the two groups at last follow-up ( P>0.05). Conclusion: In the treatment of mild to moderate thoracolumbar burst fractures with posterior short-segment fixation, the instrumentation of long screws in the injured vertebrae does not affect the reduction of the fracture fragments in the spinal canal. DRISF can better maintain the restored anterior height of the fractured vertebra and reduce the loss of kyphosis Cobb angle during the follow-up, indicating a better long-term effectiveness.

High Expression of PRSS3 Indicates Unfavorable Clinical Outcomes in Colon Adenocarcinoma.

INTRODUCTION: Serine proteases have been implicated as key drivers and facilitators of cancer malignancy. Protease, serine, 3 (PRSS3), which belongs to the serine proteases family, is reported to be abundantly expressed in a variety of types of tumor and contributes to the initiation and development of cancers. However, the clinical role of PRSS3 in colon adenocarcinoma (CAC) was not clarified yet. In the present study, we explored the potential effect of PRSS3 in CAC and whether it is related to the poor survival of CAC patients. MATERIALS AND METHODS: The mRNA and protein levels of PRSS3 were examined in CAC samples and connective noncancerous colon samples through quantitative real-time polymerase chain reaction assay and immunohistochemistry staining. Univariate and multivariate analyses were performed to estimate the prognostic role of PRSS3 in enrolled CAC patients. RESULTS: PRSS3 expression in CAC samples was significantly increased compared with connective noncancerous samples. Moreover, a higher level of PRSS3 was found to be correlated with the larger tumor size, advanced T stage, and positive lymph node metastasis. In addition, PRSS3 was also defined as an unfavorable prognosis factor for CAC patients. CONCLUSIONS: High expression of PRSS3 was significantly related to the unfavorable clinical features and poor prognosis in CAC patients. It suggested that PRSS3 might serve as a novel prognostic indicator and potential drug target for CAC treatment.

Knockdown of miR-125b-5p inhibits the proliferation and invasion of gastric carcinoma cells by targeting RYBP.

Gastric carcinoma, one of the most aggressive and lethal human malignancies, is associated with poor prognosis despite progress in therapeutic strategies. This study examined the potential function and mechanism of action of microRNA-125b-5p (miR-125b-5p) in the pathogenesis of gastric carcinoma. We recognized that miR-125b-5p was elevated in gastric carcinoma, and its decreased expression was associated with a better prognosis. Loss-of-function assays showed that miR-125b-5p suppression inhibited the proliferative and invasive abilities of gastric cancer cells. Furthermore, RING1 and YY1-binding protein (RYBP) was found to be target gene for miR-125b-5p action; miR-125b-5p negatively regulates RYBP expression. According to the results of rescue experiments, RYBP downregulation partially counteracted the miR-125b-5p silence-mediated inhibitory function in gastric cancer progression. Collectively, these data elucidated the molecular mechanisms of the miR-125b-5p/RYBP axis in gastric cancer invasion and growth.

[Surgical treatment of delayed spinal cord injury caused by atypical compression of old thoracolumbar fractures].

OBJECTIVE: To explore the clinical characteristics and surgical treatment strategies of delayed spinal cord injury (SCI) caused by atypical compression of old thoracolumbar fracture. METHODS: Between January 2011 and June 2018, 32 patients with delayed SCI caused by atypical compression of old thoracolumbar fracture who met the inclusion criteria were admitted and divided into group A (20 cases, underwent anterior subtotal vertebral body resection+titanium mesh reconstruction+screw rod internal fixation) and group B (12 cases, underwent posterior 270° ring decompression of vertebral canal+titanium mesh reconstruction+screw rod internal fixation) according to the different operation approaches. There was no significant difference between the two groups in age, gender, cause of injury, fracture segment, disease duration, preoperative American Spinal Injury Association (ASIA) classification, and preoperative back pain visual analogue scale (VAS) score, lumbar Japanese Orthopaedic Association (JOA) score, kyphosis angle, and vertebral canal occupational ratio ( P>0.05). The incision length, operation time, intraoperative blood loss, complications, and bone fusion time of reconstructed vertebrae were recorded and compared between the two groups; the kyphosis angle, back pain VAS score, and lumbar JOA score were used to evaluate the effectiveness. RESULTS: Except that the incision length in group A was significantly shorter than that in group B ( t=-4.865, P=0.000), there was no significant difference in intraoperative blood loss and operation time between the two groups ( P>0.05). There was no deaths or postoperative paraplegia cases in the two groups, and no deep infection or skin infection occurred. There was 1 case of cerebrospinal fluid leakage, 1 case of inferior vena cava injury, and 1 case of chyle leakage in group A. No serious complications occurred in group B. There was no significant difference in the incidence of complications between the two groups ( P=0.274). All 32 patients were followed up 12-61 months, with an average of 20.8 months. The follow-up time for groups A and B were (19.35±5.30) months and (23.25±12.20) months respectively, and the difference was not significant ( t=-1.255, P=0.219). The reconstructed vertebrae in all cases obtained bony fusion postoperatively. The fusion time of groups A and B were (8.85±2.27) months and (8.50±2.50) months respectively, and the difference was not significant ( t=0.406, P=0.688). The kyphosis angle, back pain VAS score, and lumbar JOA score of the two groups at each time point after operation and last follow-up were significantly improved when compared with preoperatively ( P<0.05); the lumbar JOA score was further improved with time postoperatively ( P<0.05), while the kyphosis angle and the VAS score of back pain remained similarly ( P>0.05). Comparison of kyphosis angle, back pain VAS score, and lumbar JOA score between the two groups at various time points postoperatively showed no significant difference ( P>0.05). At last follow-up, the JOA score improvement rate in groups A and B were 83.87%±0.20% and 84.50%±0.14%, respectively, and the difference was not significant ( t=-0.109, P=0.914); the surgical treatment effects of the two groups were judged to be significant. CONCLUSION: In the later stage of treatment of old thoracolumbar fractures, even mild kyphosis and spinal canal occupying may induce delayed SCI. Surgical correction and decompression can significantly promote the recovery of damaged spinal cord function. Compared with anterior approach surgery, posterior approach surgery has the advantages of less trauma, convenient operation, and fewer complications, so it can be preferred.

Circular RNA_CNST Promotes the Tumorigenesis of Osteosarcoma Cells by Sponging miR-421.

Circular RNAs (circRNAs) act crucial roles in the progression of multiple malignancies including osteosarcoma (OS). But, the underlying mechanisms by which hsa_circ_0017311 (circCNST) contributes to the tumorigenesis of OS remain poorly understood. Our present study aimed to explore the role and mechanisms of circCNST in OS tumorigenesis. The differentially expressed circRNAs were identified by the Gene Expression Omnibus database. The association of circCNST with clinicopathological features and prognosis in patients with OS was analyzed by RNA fluorescence in situ hybridization (FISH) and quantitative real-time polymerase chain reaction (PCR) analysis. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation assays, and a xenograft tumor model were conducted to assess the role of circCNST in OS cells in vitro and in vivo. CircCNST-specific binding with miR-421 was confirmed by FISH, luciferase gene report, and RNA immunoprecipitation assays. As a result, we found that the expression levels of circCNST were dramatically increased in OS tissues and cell lines as compared with the adjacent normal tissues, and it was associated with tumor size and poor survival in OS patients. Knockdown of circCNST repressed cell viability, colony formation, and xenograft tumor growth, while restored expression of circCNST reversed these effects. Furthermore, circCNST was colocalized with miR-421 in the cytoplasm and acted as a sponge of miR-421, which attenuated circCNST-induced proliferation-promoting effects in OS cells by targeting SLC25A3. In conclusion, our findings demonstrate that circCNST promotes the tumorigenesis of OS cells by sponging miR-421, and provides a potential biomarker for patients with OS.

Magnesium Lithospermate B Protects against Lipopolysaccharide-Induced Bone Loss by Inhibiting RANKL/RANK Pathway.

Lipopolysaccharide (LPS) can induce bone loss by stimulating bone resorption. Natural compounds have great potential for the treatment of osteolytic bone diseases. Magnesium lithospermate B (MLB) plays an important role in protecting against oxidative damage and also has potential anti-inflammatory pharmacological properties. However, its role in LPS-induced bone loss is still unknown. In the present study, we observed the effects of MLB on LPS-induced bone damage and investigated the possible mechanisms. The bone loss models were established by LPS administration in male Sprague-Dawley rats. MLB (200 mg/kg body weight) was given by subcutaneous injection. MicroCT analysis, biomarker assay, histological examination and immunohistochemical staining were performed at the 8th weeks. In addition, RAW264.7 cells were treated with LPS in the presence or absence of MLB. The osteoclast formation, resorption activity and differentiation-related genes [(receptor activator of nuclear factor kappa-B (RANK), Traf6, Fra-1, and c-src)] expression were evaluated. LPS induced bone loss shown as the decrease in bone volume fraction and trabecular number, and increase in trabecular separation. LPS also markedly enhanced the osteoclast formation and resorption activity compared with the control. MLB significantly abolished the LPS-induced bone microstructure damage (p < 0.05) and osteoclast formation. MLB also inhibited the increases of serum tartrate-resistant acid phosphatase 5b, RANK ligand (RANKL) and TNF-α level enhanced by LPS (p < 0.05). Immunohistochemical staining indicated that MLB attenuated the high expression of RANKL and RANK stimulated by LPS. In addition, MLB significantly abolished the LPS-enhanced osteoclast formation, resorption activity, RANK, Traf6, Fra-1, and c-src expression in vitro. Our data demonstrate that MLB can suppress LPS-induced bone loss via inhibiting RANKL/RANK related osteoclast formation.