PTHR1 in osteosarcoma: Specific molecular mechanisms and comprehensive functional perspective

MTF2 facilitates the advancement of osteosarcoma through mediating EZH2/SFRP1/Wnt signaling

BACKGROUND

Osteosarcoma is a soft tissue neoplasm with elevated recurrence risk and highly metastatic potential. Metal response element binding transcriptional factor 2 (MTF2) has been revealed to exert multiple activities in human tissues. The present research was conducted to explore the functions and related response mechanism of MTF2 in osteosarcoma which have not been introduced yet.

METHODS

Bioinformatics tools identified the differential MTF2 expression in osteosarcoma tissues. MTF2 expression in osteosarcoma cells was examined with Western blot. Cell Counting Kit-8 (CCK-8) assay, 5-Ethynyl-2'-deoxyuridine (EDU) staining, wound healing as well as transwell assays measured cell proliferation, migration and invasion, respectively. Flow cytometry assay detected the cellular apoptotic level. Western blot also measured the expressions of proteins associated with epithelial mesenchymal transition (EMT), apoptosis and enhancer of zeste homolog 2 (EZH2)/secreted frizzled-related protein 1 (SFRP1)/Wnt signaling. Co-immunoprecipitation (Co-IP) assay confirmed MTF2-EZH2 interaction.

RESULTS

MTF2 expression was increased in osteosarcoma tissues and cells. MTF2 interference effectively inhibited the proliferation, migration and invasion of osteosarcoma cells and promoted the cellular apoptotic rate. MTF2 directly bound to EZH2 and MTF2 silence reduced EZH2 expression, activated SFRP1 expression and blocked Wnt signaling in osteosarcoma cells. EZH2 upregulation or SFRP1 antagonist WAY-316606 partly counteracted the impacts of MTF2 down-regulation on the SFRP1/Wnt signaling and the biological phenotypes of osteosarcoma cells.

CONCLUSIONS

MTF2 might down-regulate SFRP1 to activate Wnt signaling and drive the progression of osteosarcoma via interaction with EZH2 protein.

Identification of a pro-protein synthesis osteosarcoma subtype for predicting prognosis and treatment

Osteosarcoma (OS) is a heterogeneous malignant spindle cell tumor that is aggressive and has a poor prognosis. Although combining surgery and chemotherapy has significantly improved patient outcomes, the prognosis for OS patients with metastatic or recurrent OS has remained unsatisfactory. Therefore, it is imperative to gain a fresh perspective on OS development mechanisms and treatment strategies. After studying single-cell RNA sequencing (scRNA-seq) data in public databases, we identified seven OS subclonal types based on intra-tumor heterogeneity. Subsequently, we constructed a prognostic model based on pro-protein synthesis osteosarcoma (PPS-OS)-associated genes. Correlation analysis showed that the prognostic model performs extremely well in predicting OS patient prognosis. We also demonstrated that the independent risk factors for the prognosis of OS patients were tumor primary site, metastatic status, and risk score. Based on these factors, nomograms were constructed for predicting the 3- and 5-year survival rates. Afterward, the investigation of the tumor immune microenvironment (TIME) revealed the vital roles of γδ T-cell and B-cell activation. Drug sensitivity analysis and immune checkpoint analysis identified drugs that have potential application value in OS. Finally, the jumping translocation breakpoint (JTB) gene was selected for experimental validation. JTB silencing suppressed the proliferation, migration, and invasion of OS cells. Therefore, our research suggests that PPS-OS-related genes facilitate the malignant progression of OS and may be employed as prognostic indicators and therapeutic targets in OS.

Unveiling the Protective Role of Melatonin in Osteosarcoma: Current Knowledge and Limitations

Melatonin, an endogenous neurohormone produced by the pineal gland, has received increased interest due to its potential anti-cancer properties. Apart from its well-known role in the sleep-wake cycle, extensive scientific evidence has shown its role in various physiological and pathological processes, such as inflammation. Additionally, melatonin has demonstrated promising potential as an anti-cancer agent as its function includes inhibition of tumorigenesis, induction of apoptosis, and regulation of anti-tumor immune response. Although a precise pathophysiological mechanism is yet to be established, several pathways related to the regulation of cell cycle progression, DNA repair mechanisms, and antioxidant activity have been implicated in the anti-neoplastic potential of melatonin. In the current manuscript, we focus on the potential anti-cancer properties of melatonin and its use in treating and managing pediatric osteosarcoma. This aggressive bone tumor primarily affects children and adolescents and is treated mainly by surgical and radio-oncological interventions, which has improved survival rates among affected individuals. Significant disadvantages to these interventions include disease recurrence, therapy-related toxicity, and severe/debilitating side effects that the patients have to endure, significantly affecting their quality of life. Melatonin has therapeutic effects when used for treating osteosarcoma, attributed to its ability to halt cancer cell proliferation and trigger apoptotic cell death, thereby enhancing chemotherapeutic efficacy. Furthermore, the antioxidative function of melatonin alleviates harmful side effects of chemotherapy-induced oxidative damage, aiding in decreasing therapeutic toxicities. The review concisely explains the many mechanisms by which melatonin targets osteosarcoma, as evidenced by significant results from several in vitro and animal models. Nevertheless, if further explored, human trials remain a challenge that could shed light and support its utility as an adjunctive therapeutic modality for treating osteosarcoma.

Lead optimization of pyrido[2,3-d][1]benzazepin-6-one derivatives leading to the discovery of a potent, selective, and orally available human parathyroid hormone receptor 1 (hPTHR1) antagonist (DS69910557)

We report the discovery of a series of novel zwitterionic hPTHR1 antagonists. Optimization of lead compound 2 led to 4-[[1-[4-(2,9-dichloro-5,5-dimethyl-6-oxo-pyrido[2,3-d][1]benzazepin-7-yl)phenyl]-3-fluoro-azetidin-3-yl]methylamino]cyclohexanecarboxylic acid (19e, DS69910557), a compound with excellent potency and selectivity over activity at the human ether-a-go-go-related-gene (hERG) channel. Compound 19e demonstrated in vivo potency to decrease the plasma calcium concentration in rats upon oral administration. 2022 Elsevier Ltd. All rights reserved.

MicroRNAs and osteosarcoma: Potential targets for inhibiting metastasis and increasing chemosensitivity

Osteosarcoma (OS) is the third most common cancer in young adults after lymphoma and brain cancer. Metastasis, like other cellular events, is dependent on signaling pathways; a series of changes in some proteins and signaling pathways pave the way for OS cells to invade and migrate. Ezrin, TGF-β, Notch, RUNX2, matrix metalloproteinases (MMPs), Wnt/β-catenin, and phosphoinositide 3-kinase (PI3K)/AKT are among the most important of these proteins and signaling pathways. Despite the improvements in treating OS, the overall survival of patients suffering from the metastatic disease has not experienced any significant change after surgical treatments and chemotherapy and 5-years overall survival in patients with metastatic OS is about 20%. Studies have shown that overexpression or inhibition of some microRNAs (miRNAs) has significant effects in limiting the invasion and migration of OS cells. The results of these studies highlight the potential of the clinical application of some miRNA mimics and miRNA inhibitors (antagomiRs) to inhibit OS metastasis in the future. In addition, some studies have shown that miRNAs are associated with the most important drug resistance mechanisms in OS, and some miRNAs are highly effective targets to increase chemosensitivity. The results of these studies suggest that miRNA mimics and antagomiRs may be helpful to increase the efficacy of conventional chemotherapy drugs in the treatment of metastatic OS. In this article, we discussed the role of various signaling pathways and the involved miRNAs in the metastasis of OS, attempting to provide a comprehensive review of the literature on OS metastasis and chemosensitivity.

Prediction and Identification of GPCRs Targeting for Drug Repurposing in Osteosarcoma

Background

Osteosarcoma (OS) is a malignant bone tumor common in children and adolescents. The 5-year survival rate is only 67-69% and there is an urgent need to explore novel drugs effective for the OS. G protein-coupled receptors (GPCRs) are the common drug targets and have been found to be associated with the OS, but have been seldom used in OS.

Methods

The GPCRs were obtained from GPCRdb, and the GPCRs expression profile of the OS was downloaded from the UCSC Xena platform including clinical data. 10-GPCRs model signatures related to OS risk were identified by risk model analysis with R software. The predictive ability and pathological association of the signatures in OS were explored by bio-informatics analysis. The therapeutic effect of the target was investigated, followed by the investigation of the targeting drug by the colony formation experiment were.

Results

We screened out 10 representative GPCRs from 50 GPCRs related to OS risk and established a 10-GPCRs prognostic model (with CCR4, HCRTR2, DRD2, HTR1A, GPR158, and GPR3 as protective factors, and HTR1E, OPN3, GRM4, and GPR144 as risk factors). We found that the low-risk group of the model was significantly associated with the higher survival probability, with the area under the curve (AUC) of the ROC greater than 0.9, conforming with the model. Moreover, both risk-score and metastasis were the independent risk factor of the OS, and the risk score was positively associated with the metastatic. Importantly, the CD8 T-cells were more aggregated in the low-risk group, in line with the predict survival rate of the model. Finally, we found that DRD2 was a novel target with approved drugs (cabergoline and bromocriptine), and preliminarily proved the therapeutic effects of the drugs on OS. These novel findings might facilitate the development of OS drugs.

Conclusion

This study offers a satisfactory 10-GPCRs model signature to predict the OS prognostic, and based on the model signature, candidate targets with approved drugs were provided.

PTHR1 in osteosarcoma: Specific molecular mechanisms and comprehensive functional perspective

Osteosarcoma occurs largely in children and adolescents and is the most common primary malignant tumour of bone. Although surgical advances and neoadjuvant chemotherapy have made great strides in recent years, rates of local recurrence and lung metastasis remain high, with a plateau in overall survival during the past decade. It is thus urgent to explore the pathogenesis of osteosarcoma and identify potential therapeutic targets. Parathyroid hormone receptor 1 (PTHR1) belongs to the broad family of G protein–coupled receptors, binding both parathyroid hormone (PTH) and parathyroid hormone–related peptide (PTHrP, a paracrine factor). Previous studies have shown that in tissues and cells of osteosarcoma, expression of PTHR1 is markedly increased, correlating with aggressive biologic behaviour and a poor prognosis. PTHR1 expression also correlates closely with epigenetic regulation, transcriptional regulation, post‐translational modification and protein interaction. Herein, we have summarized the latest research on the role played by PTHR1 in progression of osteosarcoma, assessing its clinical utility as a novel biomarker and its therapeutic ramifications.