The effect of preoperative radiotherapy on local control and prognosis in high-grade non-metastatic intramedullary osteosarcoma of the extremities

NUCKS1, a LINC00629-upregulated gene, facilitated osteosarcoma progression and metastasis by elevating asparagine synthesis

Nuclear ubiquitous casein and cyclin-dependent kinase substrate 1 (NUCKS1) has been reported to play an oncogenic role in several cancers. However, the biological functions and regulatory mechanism of NUCKS1 in osteosarcoma have not been fully understood. In this study, we reported that NUCKS1 was significantly increased in osteosarcoma. Depletion of NUCKS1 decreased osteosarcoma cell proliferation and metastasis in vivo and in vitro. Overexpression of NUCKS1 accelerated osteosarcoma cell aggressiveness. Mechanistically, NUCKS1 facilitated asparagine (Asn) synthesis by transcriptionally upregulating asparagine synthetase (ASNS) expression and elevating the levels of Asn in osteosarcoma cells, leading to increased cell growth and metastasis. Inhibition of ASNS or reduction of Asn decreased osteosarcoma cell aggressiveness and impaired the promoting effects of NUCKS1 on tumorigenesis and metastasis. Furthermore, we also found that by acting as a sponge for miR-4768-3p, LINC00629 promoted NUCKS1 expression. Collectively, our findings highlight the role of NUCKS1 in regulating asparagine metabolism and reveal that LINC00629 is an important regulator of NUCKS1 that contributes to NUCKS1 upregulation in osteosarcoma.

NEK6 Promotes the Progression of Osteosarcoma Through Activating STAT3 Signaling Pathway by Down-Regulation of miR-26a-5p

Background

Osteosarcoma is a malignant tumor originating from the skeletal system. There is no effective treatment other than surgery and chemotherapy, which seriously endangers the health of children and adolescents. NEK6 is a novel discovered Serine/Threonine protein kinase that can regulate cell cycle and activate several oncogenic pathways.

Methods

NEK6 expression in pan-cancer including sarcoma was evaluated using analysis tools of TIMER, UALCNA and GEPIA with TCGA database, and its association with overall survival in patients with sarcoma was also analyzed. TargetScan, tarbase, microT-CDS and Starbase online software were used to predict NEK6-targeted miRNAs, including miR-26a-5p. Tumor tissues from patients with osteosarcoma were collected for NEK6 and miRNA detection using RT-qPCR. NEK6 down-regulated by siRNAs or miR-26a-5p in osteosarcoma cells was detected by RT-qPCR, Western blot and Immunofluorescence staining assays. Effects of NEK6 knockdown on proliferation, migration, invasion and apoptosis of osteosarcoma cells were detected by CCK-8, wound healing, transwell and flow cytometry, respectively. The expressions of STAT3, metastasis and apoptosis-related genes were detected by Western blot.

Results

High expression of NEK6 and low expression of miR-26a-5p were lowly expressed in osteosarcoma and they were negative correlation. NEK6 has been confirmed as a direct target for miR-26a-5p. In addition, NEK6 down-regulated by siRNAs or miR-26a-5p led to inhibition of cell proliferation, migration and invasion while promoting cell apoptosis. The levels of phosphorylated STAT3 and metastasis genes (MMP-2, MMP-9) were inhibited, while apoptotic gene Bax was promoted and Bcl2 was inhibited by miR-26a-5p upregulation.

Conclusion

NEK6 can promote osteosarcoma progression via activating STAT3 signaling pathway, which is inhibited by miR-26a-5p, suggesting that NEK6 is a potential oncogene and miR-26a-5p is a suppressor of osteosarcoma. The strategy of inhibiting of NEK6 by miR-26a-5p may be an effective approach for osteosarcoma therapy.

LINC00629 protects osteosarcoma cell from ER stress-induced apoptosis and facilitates tumour progression by elevating KLF4 stability

BACKGROUND

Escaping from ER stress-induced apoptosis plays an important role in the progression of many tumours. However, its molecular mechanism in osteosarcoma remains incompletely understood.

METHODS

The molecular mechanism was investigated using RNA sequencing, qRT-PCR and Western blot assays. The relationship between LINC00629 and KLF4 was investigated using RNA pulldown and ubiquitylation assays. The transcriptional regulation of laminin subunit alpha 4 (LAMA4) by KLF4 was identified using bioinformatic analysis, a luciferase assay, and a chromatin immunoprecipitation assay.

RESULTS

Here, we demonstrated that LINC00629 was increased under ER stress treatment. Elevated LINC00629 inhibited ER stress-induced osteosarcoma cell apoptosis and promoted clonogenicity and migration in vitro and in vivo. Further mechanistic studies indicated that LINC00629 interacted with KLF4 and suppressed its degradation, which led to a KLF4 increase in osteosarcoma. In addition, we also found that KLF4 upregulated LAMA4 expression by directly binding to its promoter and that LINC00629 inhibited ER stress-induced apoptosis and facilitated osteosarcoma cell clonogenicity and metastasis by activating the KLF4-LAMA4 pathway.

CONCLUSION

Collectively, our data indicate that LINC00629 is a critical long noncoding RNA (lncRNA) induced by ER stress and plays an oncogenic role in osteosarcoma cell by activating the KLF4-LAMA4 axis.

Identification of Small-Molecule Inhibitors for Osteosarcoma Targeted Therapy: Synchronizing In Silico, In Vitro, and In Vivo Analyses

Objective: The study aimed to explore a new approach for the treatment of osteosarcoma through combining biomaterials with next-generation small molecule–based targeted therapy.

Methods: The model of osteosarcoma was established by 4-hydroxyaminoquinoline 1-oxide (4-HAQO) in mice while the collagen-thermosensitive hydrogel–calcium phosphate (CTC) biocomposites were prepared, and the small molecule inhibitors were virtually screened and synthesized. Then, for the osteosarcoma cell line, MG-63 cells were used to validate our bioinformatic findings in vitro, and the mouse osteosarcoma models were treated by combing CTC composites and small-molecule inhibitors after debridement.

Results: Five compounds, namely, ZINC150338698, ZINC14768621, ZINC4217203, ZINC169291448, and ZINC85537017, were found in the ZINK database. Finally, ZINC150338698 was selected for chemical synthesis and experimental verification. The results of the MTT assay and Hoechst staining showed that the small-molecule inhibitor ZINC150338698 could significantly induce MG-63 cell death. Furthermore, CTC composites and ZINC150338698 could repair the bone defects well after the debridement of osteosarcoma. In addition, the biomaterials and small-molecule inhibitors have good biocompatibility and biosafety.

Conclusion: Our findings not only offer systems biology approach-based drug target identification but also provide new clues for developing novel treatment methods for future osteosarcoma research.

Development and Validation of Nomogram-Based Prognosis Tools for Patients with Extremity Osteosarcoma: A SEER Population Study

Objective

Osteosarcoma, usually occurring in the extremities, is the most common malignant bone tumour. The purpose of this study is to develop and validate nomogram-based prognosis tools for survival (OS) and cancer special survival (CSS) of patients with osteosarcoma of the extremities via the application of survival analysis.

Materials and Methods

A total of 1427 patients diagnosed with osteosarcoma of the extremities during 2004–2015 were selected from the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results- (SEER-) Medicare database. The samples were randomly assigned to either the training set (n = 856) or the validation cohort (n = 571). Kaplan–Meier (K–M) survival analysis was conducted to calculate patients' 1-, 3-, and 5-year OS and CSS rates. Cox proportional hazard ratio (HR) regression models were employed to identify and examine the factors that have a significant impact on OS and CSS with data from the training cohort.

Results

The results of univariate and multivariate analyses performed in the training cohort indicated that older age, increased tumour size, higher grade, distant tumour extension, amputation, or no surgery (all HR > 1, P < 0.05) were risk predictors of poor OS and CSS. Subsequently, the independent prognosis signatures were utilised to construct nomograms. The concordance index (C-index), calibration plot, and decision curve analysis (DCA) were simultaneously used to validate the nomograms. The internally validated C-index values of the OS and CSS prediction models for the training set were 0.752 (95% confidence interval [CI]: 0.738–0.765) and 0.754 [95% CI: 0.740–0.768], respectively. Then, the models were validated in the validation cohort population, which also demonstrated the models had good reliability for prognostication.

Conclusions

The SEER cohort of patients with osteosarcoma of the extremities can be employed to produce effective tools that can assist in prognosis modelling.

The risk factors for mechanical complication in endoprosthetic reconstruction of knee osteosarcoma

BACKGROUND

The increased limb survival rates and higher functional demands have also increased the mechanical complication rates of megaprostheses. This study aimed to analyse possible risk factors which can predispose patients to mechanical complications.

METHODS

Patients with knee osteosarcoma referred to our clinic from 1992 to 2014 were investigated retrospectively. The patients who underwent surgical resection and endoprosthetic reconstruction with at least 5 years of follow up were analysed. The revision of the megaprosthesis due to a mechanical complication was accepted as an endpoint. The possible risk factors, including cement usage, implant material, joint mechanism, neoadjuvant radiotherapy, and anatomical localization of the lesion, were analysed for any association with mechanical complication rates.

RESULTS

A total of 118 patients were included for final analysis. The average age was 24.5 years (standard deviation ±10.1, range: 15-64). Mechanical complication rate was 22% which included 19 aseptic loosenings and seven implant failures. The average time to mechanical complication was 32.5 months. Overall, 5-year implant survival was 78%. Multiple regression analysis revealed that cement usage is an independent risk factor for mechanical complication (P = 0.007). Although the 5-year implant survival was higher in rotating hinge and titanium implants compared with fixed hinge and cobalt chrome, the multiple regression model did not yield a correlation with mechanical complication rates.

CONCLUSION

Cemented implants showed significantly higher mechanical complication rates compared with cementless ones in this series of knee osteosarcoma patients who underwent megaprosthetic reconstruction. Hinge mechanism and implant material did not have a significant effect on mechanical complication rates.

Knockdown of lncRNA C5orf66-AS1 inhibits osteosarcoma cell proliferation and invasion via miR-149-5p upregulation

Osteosarcoma (OS) is the most common primary malignant bone tumor in the pediatric age group. Despite the various potential treatments for OS, the cure rate of patients with OS remains very low. An increasing number of long non-coding RNAs (lncRNAs) have been identified as key regulators of the progression of malignant human tumors. However, the biological functions of the lncRNA C5orf66-antisense 1 (C5orf66-AS1) in OS are yet to be fully elucidated. The present study aimed to investigate the functions and underlying mechanisms of C5orf66-AS1 in OS tissues and cell lines. Expression levels of C5orf66-AS1 and microRNA (miRNA/miR)-149-5p in tissues from patients with OS and OS cells lines were evaluated using reverse transcription quantitative (RT-q)PCR. The miRNA target interaction between C5orf66-AS1 and miR-149-5p was predicted and verified using StarBase and dual-luciferase reporter assays. Cell viability, migration, invasion and apoptosis were analyzed using Cell Counting Kit-8, Transwell assays and flow cytometry, respectively. In addition, the expression levels of migration- and apoptosis-associated proteins [matrix metalloproteinase-9 (MMP-9), Bcl-2 and Bax] were determined using western blotting and RT-qPCR. The results demonstrated that C5orf66-AS1 was significantly upregulated and miR-149-5p was significantly downregulated in OS tissues and cells (MG63 and U2OS). Bioinformatics analysis further confirmed that miR-149-5p could directly bind to C5orf66-AS1. Furthermore, it was revealed that C5orf66-AS1 negatively regulated the expression of miR-149-5p in OS cells, as confirmed by the inhibition of C5orf66-AS1 expression and miR-149-5p upregulation in cells transfected with small interfering (si RNA targeting C5orf66-AS1. In addition, C5orf66-AS1 silencing significantly inhibited the proliferation, invasion and migration of U2OS cells, and stimulated cell apoptosis. These findings were reversed using miR-149-5p inhibitor. Increased Bax expression and decreased Bcl-2 and MMP-9 expression were also observed in C5orf66-AS1-siRNA transfected U2OS cells, compared with the control group. In summary, the results from the present study indicated that C5orf66-AS1 knockdown inhibits OS cell proliferation and invasion via the upregulation of miR-149-5p. This findings may provide a promising novel target for the treatment of OS.

Radiotherapy in the Management of Pediatric and Adult Osteosarcomas: A Multi-Institutional Cohort Analysis

Background: Due to the rarity of osteosarcoma and limited indications for radiotherapy (RT), data on RT for this tumor are scarce. This study aimed to investigate the utilization of RT for osteosarcomas in the recent 20 years and to identify factors related to patients’ response to radiation. Methods: We performed a retrospective analysis of patients irradiated for osteosarcoma treatment. We planned to assess differences in the utilization of RT between the periods of 2000–2010 and 2011–2020, identify the risk factors associated with local progression (LP), determine whether RT-related parameters are associated with LP, and calculate patients’ survival. Results: A total of 126 patients with osteosarcoma who received 181 RT treatments were identified. We found a difference in RT techniques between RT performed in the years 2000–2010 and that performed in the years 2011–2020. LP was observed after 37 (20.4%) RT treatments. Intent of RT, distant metastases, and concomitant systemic treatment affected the risk of LP. Five-year overall survival was 33% (95% confidence interval (26%–43%)). Conclusions: RT for osteosarcoma treatment has evolved from simple two-dimensional palliative irradiation into more conformal RT applied for new indications including oligometastatic and oligoprogressive disease. RT may be a valuable treatment modality for selected patients with osteosarcoma.