Molecular mechanisms of osteosarcoma metastasis and possible treatment opportunities

Groenlandicine enhances cisplatin sensitivity in cisplatin-resistant osteosarcoma cells through the BAX/Bcl-2/Caspase-9/Caspase-3 pathway

Groenlandicine is a protoberberine alkaloid isolated from Coptidis Rhizoma, a widely used traditional Chinese medicine known for its various biological activities. This study aims to validate groenlandicine's effect on both cisplatin-sensitive and cisplatin-resistant osteosarcoma (OS) cells, along with exploring its potential molecular mechanism. The ligand-based virtual screening (LBVS) method and molecular docking were employed to screen drugs. CCK-8 and FCM were used to measure the effect of groenlandicine on the OS cells transfected by lentivirus with over-expression or low-expression of TOP1. Cell scratch assay, CCK-8, FCM, and the EdU assay were utilized to evaluate the effect of groenlandicine on cisplatin-resistant cells. WB, immunofluorescence, and PCR were conducted to measure the levels of TOP1, Bcl-2, BAX, Caspase-9, and Caspase-3. Additionally, a subcutaneous tumor model was established in nude mice to verify the efficacy of groenlandicine. Groenlandicine reduced the migration and proliferation while promoting apoptosis in OS cells, effectively damaging them. Meanwhile, groenlandicine exhibited weak cytotoxicity in 293T cells. Combination with cisplatin enhanced tumor-killing activity, markedly activating BAX, cleaved-Caspase-3, and cleaved-Caspase-9, while inhibiting the Bcl2 pathway in cisplatin-resistant OS cells. Moreover, the level of TOP1, elevated in cisplatin-resistant OS cells, was down-regulated by groenlandicine both in vitro and in vivo. Animal experiments confirmed that groenlandicine combined with cisplatin suppressed OS growth with lower nephrotoxicity. Groenlandicine induces apoptosis and enhances the sensitivity of drug-resistant OS cells to cisplatin via the BAX/Bcl-2/Caspase-9/Caspase-3 pathway. Groenlandicine inhibits OS cells growth by down-regulating TOP1 level.Therefore, groenlandicine holds promise as a potential agent for reversing cisplatin resistance in OS treatment.

Single-cell RNA sequencing reveals the communications between tumor microenvironment components and tumor metastasis in osteosarcoma

Introduction

Osteosarcoma is a common type of bone cancer characterized by a poor prognosis due to its metastatic nature. The tumor microenvironment (TME) plays a critical role in tumor metastasis and therapy response. Therefore, our study aims to explore the metastatic mechanism of osteosarcoma, potentially opening new avenues for cancer treatment.

Methods

In this study, we collected data from the GSE152048, GSE14359, and GSE49003 datasets. Differentially expressed genes (DEGs) were identified in osteosarcoma cases with primary and metastatic features using R software and the limma package. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to investigate metastasis-related genes. A protein-protein interaction (PPI) network was established using the STRING database to further analyze these metastasis-associated genes. The abundances of different cell types with a mixed cell population were estimated using the CIBERSORT approach. The scRNA-seq data were analyzed by the Seurat package in R software, and intercellular communications were elucidated using the CellChat R package.

Results

In this study, 92 DEGs related to metastasis were identified, including 41 upregulated and 51 downregulated genes in both the GSE14359 and GSE49003 datasets. Metastasis-associated pathways were identified, including those involving the cyclin-dependent protein kinase holoenzyme complex, transferase complex, transferring phosphorus-containing groups, SCF ubiquitin ligase complex, and the serine/threonine protein kinase complex. KEGG and PPI network analyses revealed 15 hub genes, including Skp2, KIF20A, CCNF, TROAP, PHB, CKS1B, MCM3, CCNA2, TRIP13, CENPM, Hsp90AB1, JUN, CKS2, TK1, and KIF4A. Skp2 has been known as an E3 ubiquitin ligase involved in osteosarcoma progression. The proportion of CD8+ T cells was found to be higher in metastatic osteosarcoma tissues, and high expression of PHB was associated with a favorable prognosis in osteosarcoma patients. Additionally, 23 cell clusters were classified into eight cell types, including chondrocytes, MSC, T cells, monocytes, tissue stem cells, neurons, endothelial cells, and macrophages. The 15 hub genes were expressed across various cell types, and interactions between different cell types were observed.

Conclusion

Our study reveals the intricate communication between tumor microenvironment components and tumor metastasis in osteosarcoma.

Mexican Multicenter Experience of Metastatic Spinal Disease

Background Spinal metastatic disease is a silent progressive cancer complication with an increasing prevalence worldwide. The spine is the third most common site where solid tumors metastasize. Complications involved in spinal metastasis include root or spinal cord compression, progressing to a declining quality of life as patient autonomy reduces and pain increases. The main objective of this study is to report the incidence of patients and typology of spinal metastases in three reference centers in Mexico. Methodology Retrospective cohorts of patients diagnosed with spinal metastases from January 2010 to February 2017 at the National Cancer Institute, National Rehabilitation Institute, and the Traumatology and Orthopedics Hospital "Lomas Verdes" in Mexico City were analyzed. Results A total of 326 patients (56% males) with spinal metastases were reported. The mean age was 58.06 ± 14.05 years. The main sources of spinal metastases were tumors of unknown origin in 53 (16.25%) cases, breast cancer in 67 (20.5%) cases, prostate cancer in 59 (18%) cases, myeloma in 24 (7.4%) cases, and lung cancer in 23 (7.1%) cases. Conclusions The data obtained in this analysis delivers an updated standpoint on Mexico, providing the opportunity to distinguish the current data from global references. Collecting more epidemiological information for better recording of cancer and its associated complications, as well as further studies on them, is necessary.

miR-1246 promotes osteosarcoma cell migration via NamiRNA-enhancer network dependent on Argonaute 2

High metastatic propensity of osteosarcoma leads to its therapeutic failure and poor prognosis. Although nuclear activation miRNAs (NamiRNAs) are reported to activate gene transcription via targeting enhancer and further promote tumor metastasis, it remains uncertain whether NamiRNAs regulate osteosarcoma metastasis and their exact mechanism. Here, we found that extracellular vesicles of the malignant osteosarcoma cells (143B) remarkably increased the migratory abilities of MNNG cells representing the benign osteosarcoma cells by two folds, which attributed to their high miR-1246 levels. Specially, miR-1246 located in nucleus could activate the migration gene expression (such as MMP1) to accelerate MNNG cell migration through elevating the enhancer activities via increasing H3K27ac enrichment. Instead, MMP1 expression was dramatically inhibited after Argonaute 2 (AGO2) knockdown. Notably, in vitro assays demonstrated that AGO2 recognized the hybrids of miR-1246 and its enhancer DNA via PAZ domains to prevent their degradation from RNase H and these protective roles of AGO2 may favor the gene activation by miR-1246 in vivo. Collectively, our findings suggest that miR-1246 could facilitate osteosarcoma metastasis through interacting with enhancer to activate gene expression dependent on AGO2, highlighting the nuclear AGO2 as a guardian for NamiRNA-targeted gene activation and the potential of miR-1246 for osteosarcoma metastasis therapy.

Hypoxia inducible factor-1ɑ as a potential therapeutic target for osteosarcoma metastasis

Osteosarcoma (OS) is a malignant tumor originating from mesenchymal tissue. Pulmonary metastasis is usually present upon initial diagnosis, and metastasis is the primary factor affecting the poor prognosis of patients with OS. Current research shows that the ability to regulate the cellular microenvironment is essential for preventing the distant metastasis of OS, and anoxic microenvironments are important features of solid tumors. During hypoxia, hypoxia-inducible factor-1α (HIF-1α) expression levels and stability increase. Increased HIF-1α promotes tumor vascular remodeling, epithelial-mesenchymal transformation (EMT), and OS cells invasiveness; this leads to distant metastasis of OS cells. HIF-1α plays an essential role in the mechanisms of OS metastasis. In order to develop precise prognostic indicators and potential therapeutic targets for OS treatment, this review examines the molecular mechanisms of HIF-1α in the distant metastasis of OS cells; the signal transduction pathways mediated by HIF-1α are also discussed.