Targeted Delivery of Chemotherapeutic Agents for Osteosarcoma Treatment

Role of proteoglycan synthesis genes in osteosarcoma stem cells

Osteosarcoma stem cells (OSCs) contribute to the pathogenesis of osteosarcoma (OS), which is the most common malignant primary bone tumor. The significance and underlying mechanisms of action of proteoglycans (PGs) and glycosaminoglycans (GAGs) in OSC phenotypes and OS malignancy are largely unknown. This study aimed to investigate the role of PG/GAG biosynthesis and the corresponding candidate genes in OSCs and poor clinical outcomes in OS using scRNA-seq and bulk RNA-seq datasets of clinical OS specimens, accompanied by biological validation by in vitro genetic and pharmacological analyses. The expression of β-1,3-glucuronyltransferase 3 (B3GAT3), one of the genes responsible for the biosynthesis of the common core tetrasaccharide linker region of PGs, was significantly upregulated in both OSC populations and OS tissues and was associated with poor survival in patients with OS with high stem cell properties. Moreover, the genetic inactivation of B3GAT3 by RNA interference and pharmacological inhibition of PG biosynthesis abrogated the self-renewal potential of OSCs. Collectively, these findings suggest a pivotal role for B3GAT3 and PG/GAG biosynthesis in the regulation of OSC phenotypes and OS malignancy, thereby providing a potential target for OSC-directed therapy.

Current Role of Topoisomerase I Inhibitors for the Treatment of Mesenchymal Malignancies and Their Potential Future Use as Payload of Sarcoma-Specific Antibody-Drug Conjugates

BACKGROUND

Topoisomerase I is an enzyme that plays a crucial part in DNA replication and transcription by the relaxation of supercoiled double-stranded DNA. Topoisomerase I inhibitors bind to the topoisomerase I cleavage complex, thereby stabilizing it and preventing the religation of the DNA strands, leading to DNA damage, cell cycle arrest, and apoptosis. Various topoisomerase I inhibitors have been evaluated in solid tumors, and irinotecan and topotecan have been approved for the treatment of epithelial malignancies. None of them have been approved for sarcoma, a diverse group of rare solid tumors with an unmet need for effective treatments.

SUMMARY

Topoisomerase I inhibitors have been evaluated in preclinical studies as single agents or in combination in solid tumors, some of which have included sarcomas where activity was observed. Clinical trials evaluating topoisomerase I inhibitors for the treatment of sarcoma have shown limited efficacy as monotherapy. In combination with other cytotoxic agents, topoisomerase I inhibitors have become part of clinical routine in selected sarcoma subtypes. Regimens such as irinotecan/vincristine/temozolomide are used in relapsed rhabdomyosarcoma, irinotecan/temozolomide and vincristine/topotecan/cyclophosphamide are commonly given in refractory Ewing sarcoma, and topotecan/carboplatin showed some activity in advanced soft tissue sarcoma. This review provides an overview of key studies with topoisomerase I inhibitors for the treatment of sarcoma. Topoisomerase I inhibitors are currently also being assessed as "payloads" for antibody-drug conjugates (ADCs), allowing for the targeting of specific antigen-expressing tumor cells and the delivery of the inhibitor directly to the tumor cells with the potential of enhancing therapeutic efficacy while minimizing systemic toxicity. Here, we also provide a brief overview on topoisomerase I-ADCs.

KEY MESSAGE

Topoisomerase I inhibitors are an important component of some systemic therapies for selected sarcomas and have potent cytotoxic properties and pharmacological characteristics that make them relevant candidates as payloads for the development of sarcoma-specific ADCs. ADCs are antibody-based targeted agents allowing for efficient and specific delivery of a given drug to the tumor cell. Topoisomerase I-ADCs are a novel targeted delivery approach which may have the potential to improve the therapeutic index of topoisomerase I inhibitors in the treatment of sarcoma and warrants investigation in a broad variety of mesenchymal malignancies.

Advances in Osteosarcoma

PURPOSE OF REVIEW

This article gives a brief overview of the most recent developments in osteosarcoma treatment, including targeting of signaling pathways, immune checkpoint inhibitors, drug delivery strategies as single or combined approaches, and the identification of new therapeutic targets to face this highly heterogeneous disease.

RECENT FINDINGS

Osteosarcoma is one of the most common primary malignant bone tumors in children and young adults, with a high risk of bone and lung metastases and a 5-year survival rate around 70% in the absence of metastases and 30% if metastases are detected at the time of diagnosis. Despite the novel advances in neoadjuvant chemotherapy, the effective treatment for osteosarcoma has not improved in the last 4 decades. The emergence of immunotherapy has transformed the paradigm of treatment, focusing therapeutic strategies on the potential of immune checkpoint inhibitors. However, the most recent clinical trials show a slight improvement over the conventional polychemotherapy scheme. The tumor microenvironment plays a crucial role in the pathogenesis of osteosarcoma by controlling the tumor growth, the metastatic process and the drug resistance and paved the way of new therapeutic options that must be validated by accurate pre-clinical studies and clinical trials.

Imatinib-Functionalized Galactose Hydrogels Loaded with Nanohydroxyapatite as a Drug Delivery System for Osteosarcoma: In Vitro Studies

This study reports an impact of structure (XRPD, FT-IR) and surface morphology (SEM-EDS) of imatinib-functionalized galactose hydrogels, loaded and unloaded with nHAp, on osteosarcoma cell (Saos-2 and U-2OS) viability, levels of free oxygen radicals, and nitric oxide, levels of BCL-2, p53, and caspase 3 and 9, as well as glycoprotein-P activity. It was investigated how the rough surface of the crystalline hydroxyapatite-modified hydrogel affected amorphous imatinib (IM) release. The imatinib drug effect on cell cultures has been demonstrated in different forms of administration-directly to the culture or the hydrogels. Administration of IM and hydrogel composites could be expected to reduce the risk of multidrug resistance development by inhibiting P_gp.

Current Status and Prospects of Targeted Therapy for Osteosarcoma

Osteosarcoma (OS) is a highly malignant tumor occurring in bone tissue with a high propensity to metastasize, and its underlying mechanisms remain largely elusive. The OS prognosis is poor, and improving the survival of OS patients remains a challenge. Current treatment methods such as surgical approaches, chemotherapeutic drugs, and immunotherapeutic drugs remain ineffective. As research progresses, targeted therapy is gradually becoming irreplaceable. In this review, several treatment modalities for osteosarcoma, such as surgery, chemotherapy, and immunotherapy, are briefly described, followed by a discussion of targeted therapy, the important targets, and new technologies for osteosarcoma treatment.

A longitudinal evaluation on 3-year change of anxiety and depression, and their risk factors among parents of childhood and adolescence patients with resectable osteosarcoma: A cohort study

Psychological disorders often occur among parents of children with cancer. The current study aimed to explore the longitudinal change of anxiety and depression and their related factors among parents of childhood and adolescence patients with osteosarcoma. A total of 56 childhood and adolescence patients with osteosarcoma who underwent tumor resection and corresponding 104 parents were enrolled. Hospital Anxiety and Depression Scale-Anxiety (HADS-A) and HADS-Depression (HADS-D) of parents were evaluated at baseline (the day of patients' hospital discharge), 0.5 year, 1 year, 2 years, and 3 years. From baseline to the 3rd year, HADS-A (from 8.3 ± 3.1 to 9.4 ± 3.1. P < .001), HADS-D score (from 7.7 ± 3.2 to 8.8 ± 2.9, P = .001), anxiety rate (from 45.2% to 60.6%, P = .038), depression rate (from 38.5% to 57.7%, P = .002) were elevated; meanwhile, anxiety severity (P = .001) and depression severity (P = .001) were also increased. Furthermore, multivariate logistic regression analysis presented that the role of mother, divorced/widowed marital status, declined family annual income, elevated Enneking stage, and amputation were independently correlated with elevated risk of parents' baseline anxiety or depression (all P < .05). Additionally, declined family annual income, elevated Enneking stage, and amputation were independently correlated with increased risk of parents' 3-year anxiety or depression (all P < .05). Anxiety and depression deteriorate with time in parents of childhood and adolescence patients with osteosarcoma, which are affected by parental role, marital status, family annual income, surgery type, and Enneking stage.

Combining bulk RNA-sequencing and single-cell RNA-sequencing data to reveal the immune microenvironment and metabolic pattern of osteosarcoma

Background: Osteosarcoma (OS) is a kind of solid tumor with high heterogeneity at tumor microenvironment (TME), genome and transcriptome level. In view of the regulatory effect of metabolism on TME, this study was based on four metabolic models to explore the intertumoral heterogeneity of OS at the RNA sequencing (RNA-seq) level and the intratumoral heterogeneity of OS at the bulk RNA-seq and single cell RNA-seq (scRNA-seq) level.

Methods: The GSVA package was used for single-sample gene set enrichment analysis (ssGSEA) analysis to obtain a glycolysis, pentose phosphate pathway (PPP), fatty acid oxidation (FAO) and glutaminolysis gene sets score. ConsensusClusterPlus was employed to cluster OS samples downloaded from the Target database. The scRNA-seq and bulk RNA-seq data of immune cells from GSE162454 dataset were analyzed to identify the subsets and types of immune cells in OS. Malignant cells and non-malignant cells were distinguished by large-scale chromosomal copy number variation. The correlations of metabolic molecular subtypes and immune cell types with four metabolic patterns, hypoxia and angiogenesis were determined by Pearson correlation analysis.

Results: Two metabolism-related molecular subtypes of OS, cluster 1 and cluster 2, were identified. Cluster 2 was associated with poor prognosis of OS, active glycolysis, FAO, glutaminolysis, and bad TME. The identified 28608 immune cells were divided into 15 separate clusters covering 6 types of immune cells. The enrichment scores of 5 kinds of immune cells in cluster-1 and cluster-2 were significantly different. And five kinds of immune cells were significantly correlated with four metabolic modes, hypoxia and angiogenesis. Of the 28,608 immune cells, 7617 were malignant cells. The four metabolic patterns of malignant cells were significantly positively correlated with hypoxia and negatively correlated with angiogenesis.

Conclusion: We used RNA-seq to reveal two molecular subtypes of OS with prognosis, metabolic pattern and TME, and determined the composition and metabolic heterogeneity of immune cells in OS tumor by bulk RNA-seq and single-cell RNA-seq.

ZCCHC12 promotes the progression of osteosarcoma via PI3K/AKT pathway

Researchers have reported that zinc finger CCHC domain containing 12 gene (ZCCHC12) plays a role in the progression and tumorigenesis of papillary thyroid cancer. However, the biological role of ZCCHC12 in osteosarcoma (OS) remains unknown. ZCCHC12 was highly upregulated in OS cell lines according to our present study. Also, our subsequent assays demonstrated that ZCCHC12 enhanced the proliferation, tumor growth and migration of OS cells. Moreover, the epithelial-mesenchymal transition (EMT) of OS cells was also promoted by ZCCHC12. In addition, downregulation of ZCCHC12 induced apoptosis and S-phase arrest in OS cells. Then, our study indicated that ZCCHC12 exerts its oncogenic function in OS cells by activating the PI3K/AKT pathway. Inhibition of the PI3K/AKT pathway greatly limits the oncogenic function of ZCCHC12 in OS cells. Also, overexpression of ZCCHC12 promotes tumor growth in vivo. Altogether, our study suggests ZCCHC12 promotes OS cells progression by activating the PI3K/AKT pathway. The ZCCHC12 gene may be a novel diagnostic and therapeutic target for OS.

LncRNA SCAMP1 disrupts the balance between miR-26a-5p and ZEB2 to promote osteosarcoma cell viability and invasion

Osteosarcoma often occurs in children and adolescents and affects their health. The survival rate of osteosarcoma patients is unsatisfactory due to the lack of early detection and metastasis development and drug resistance. Hence, dissection of molecular insight into osteosarcoma initiation and progression is pivotal to provide the new therapeutic strategy. In recent years, long noncoding RNAs (lncRNAs) have burst into stage in osteosarcoma development and malignant behaviors. LncRNA SCAMP1 has been discovered to play an essential role in carcinogenesis and progression. However, the mechanisms of lncRNA SCAMP1-involved tumorigenesis have not been reported in human osteosarcoma. In this study, we utilized multiple cellular biological approaches to determine the function of lncRNA SCAMP1 in osteosarcoma cells. Moreover, we performed several molecular biological approaches to define the mechanism by which lncRNA SCAMP1 regulated cell viability and invasion in osteosarcoma. We dissected that lncRNA SCAMP1 promoted progression of osteosarcoma via modulation of miR-26a-5p/ZEB2 axis. In conclusion, targeting lncRNA SCAMP1 and its downstream targets, miR-26a-5p and ZEB2, might be a useful approach for osteosarcoma therapy.

Curcumol Synergizes with Cisplatin in Osteosarcoma by Inhibiting M2-like Polarization of Tumor-Associated Macrophages

Osteosarcoma is the most prevalent bone cancer, and chemotherapy is still an indispensable treatment in its clinical practice. Cisplatin (CDDP) has become the most commonly used agent for osteosarcoma, although the outcomes of CDDP chemotherapy remain unsatisfactory because of frequent resistance. Here, we report on a promising combination therapy where curcumol, a bioactive sesquiterpenoid, enhanced CDDP-induced apoptosis to eradicate osteosarcoma cells, and revealed that M2-like macrophages might be the underlying associated mechanisms. First, we observed that curcumol enhanced the CDDP-mediated inhibition of cell proliferation and augmented the apoptosis in osteosarcoma cell lines. Curcumol contributed to preventing the migration of osteosarcoma cells when combined with CDDP. Moreover, this drug combination showed more potent tumor-growth suppression in the orthotopic transplantation of osteosarcoma K7M2 WT cells. We then estimated chemotherapy-associated drug-resistant genes, including ABCB1, ABCC1 and ABCG2, and found that curcumol significantly reversed the mRNA levels of CDDP-induced ABCB1, ABCC1 and ABCG2 genes in the tumor tissue. Moreover, M2-like macrophages were enriched in osteosarcoma tissues, and were largely decreased after curcumol and CDDP treatment. Taken together, these findings suggest that curcumol inhibits the polarization of M2-like macrophages and could be a promising combination strategy to synergize with CDDP in the osteosarcoma.