Targeting mutant TP53 as a potential therapeutic strategy for the treatment of osteosarcoma

The Double Life of microRNAs in Bone Sarcomas: Oncogenic Drivers and Tumor Suppressors

Bone sarcomas, including Osteosarcoma, Ewing's sarcoma, and Chondrosarcoma, are rare yet aggressive tumors with high metastatic potential and poor survival outcomes. Despite advances in surgical and chemotherapeutic techniques, these malignancies remain difficult to treat. They often exhibit resistance to conventional therapies and are associated with a limited prognosis for patients. MicroRNAs (miRNAs) have emerged as pivotal regulators of cancer biology, orchestrating crucial processes such as cell proliferation, apoptosis, and metastasis. Their double life as oncogenes or tumor suppressors underscores their significance in the pathogenesis of bone sarcomas. This review examines the multifaceted roles of miRNAs in these malignancies. By elucidating the complex networks affected by miRNA dysregulation, we seek to identify novel avenues for miRNA-based interventions. It is the intention of this work to stimulate future research and clinical strategies that exploit the potential of miRNAs to transform the management and outcomes of bone sarcomas.

Advancements in Osteosarcoma Therapy: Overcoming Chemotherapy Resistance and Exploring Novel Pharmacological Strategies

Osteosarcoma is recognized as the most prevalent primary bone malignancy, primarily affecting children and adolescents. It is characterized by its aggressive behavior and high metastatic potential, which often leads to poor patient outcomes. Despite advancements in surgical techniques and chemotherapy regimens, the prognosis for patients with osteosarcoma remains unsatisfactory, with survival rates plateauing over the past few decades. A significant barrier to effective treatment is the development of chemotherapy resistance, which complicates the management of the disease and contributes to high rates of recurrence. This review article aims to provide a comprehensive overview of recent advancements in osteosarcoma therapy, particularly in overcoming chemotherapy resistance. We begin by discussing the current standard treatment modalities, including surgical resection and conventional chemotherapy agents such as methotrexate, doxorubicin, and cisplatin. While these approaches have been foundational in managing osteosarcoma, they are often limited by adverse effects and variability in efficacy among patients. To address these challenges, we explore novel pharmacological strategies that aim to enhance treatment outcomes. This includes targeted therapies focusing on specific molecular alterations in osteosarcoma cells and immunotherapeutic approaches designed to harness the body's immune system against tumors. Additionally, we review innovative drug delivery systems that aim to improve the bioavailability and efficacy of existing treatments while minimizing toxicity. The review also assesses the mechanisms underlying chemotherapy resistance, such as drug efflux mechanisms, altered metabolism, and enhanced DNA repair pathways. By synthesizing current research findings, we aim to highlight the potential of new therapeutic agents and strategies for overcoming these resistance mechanisms. Ultimately, this article seeks to inform future research directions and clinical practices, underscoring the need for continued innovation in treating osteosarcoma to improve patient outcomes and survival rates.

CRISPR/Cas9 system: a novel approach to overcome chemotherapy and radiotherapy resistance in cancer

Cancer presents a global health challenge with rising incidence and mortality. Despite treatment advances in cancer therapy, radiotherapy and chemotherapy remained the most common treatments for all types of cancers. However, resistance phenotype in cancer cells leads to unsatisfactory results in the efficiency of therapeutic strategies. Therefore, researchers strive to propose effective solutions to overcome treatment failure, which requires a deep knowledge of treatment-resistant mechanisms. The progression and occurrence of tumors can be attributed to gene mutation. Over the past decade, the emergence of clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) genome editing has revolutionized cancer research. This versatile technology enables cancer modeling, manipulation of specific DNA sequences, and genome-wide screening. CRISPR/Cas9 is an effective tool for identifying radio- and chemoresistance genes and offering potential adjunctive treatments to overcome tumor recurrence after chemo- and radiotherapy. This article aims to explain the potential of the CRISPR/Cas9 system in improving the effectiveness of chemo- and radiotherapy and ultimately overcoming treatment failure.

Interfering with UBE2L3 expression targets regulation of MLKL to promote necroptosis inhibition of growth in osteosarcoma

BACKGROUND

In previous studies, elevated expression of UBE2L3 has been observed in osteosarcoma cells, and silencing UBE2L3 has been shown to promote oxidative stress and induce necroptosis. However, the exact molecular mechanisms underlying these findings remain unclear.

OBJECTIVE

The purpose of this study is to investigate the molecular mechanisms by which interfering with UBE2L3 expression promotes necroptosis and impacts the progression of osteosarcoma, building upon previous in vitro cell experiments.

METHODS

Osteosarcoma cells were transfected with shNC and shUBE2L3 plasmids, and the cells were injected into the right tibia of nude mice to establish a tumor xenograft model. The growth rate, changes in body weight, and tumor volume of the mice in each group were observed. After 15 days, the mice were sacrificed, and the tumors were dissected and analyzed for tumor volume. Immunohistochemical staining was performed to detect changes in the expression of necroptosis-related proteins, such as PCNA, p-MLKL, and p-RIP1. Additionally, U2OS and HOS cells were transfected with UBE2L3-silencing plasmids, and immunoprecipitation was performed to investigate the interaction between UBE2L3 and the necroptosis protein MLKL. By combining these experiments, we aim to evaluate the impact of UBE2L3 on necroptosis both in vitro and in vivo and elucidate its specific role in targeting MLKL to regulate necroptosis as a therapeutic approach for osteosarcoma.

RESULTS

After interfering with UBE2L3, the growth rate of tumors in nude mice significantly slowed down, accompanied by a notable reduction in tumor volume and weight. These findings suggest that inhibiting the expression of UBE2L3 can suppress the growth of osteosarcoma. Furthermore, immunohistochemical analysis revealed that following UBE2L3 interference, the intensity of staining for the necrotic proteins p-MLKL and p-RIP1 was increased and PCNA staining was decreased, indicating that interfering with UBE2L3 expression can promote necroptosis. Moreover, through transfection of UBE2L3 silencing plasmids into osteosarcoma cells in vitro, immunoprecipitation and ubiquitination results demonstrated that UBE2L3 can specifically bind to MLKL. Overexpression of UBE2L3 promoted the ubiquitination of MLKL and reduced its expression. Thus, down-regulation of UBE2L3 could modulate downstream MLKL expression and promote necrosis of osteosarcoma cells.

CONCLUSION

UBE2L3 selectively binds to MLKL, exerting ubiquitination-mediated regulation on downstream MLKL. Decreased expression of UBE2L3 modulates MLKL expression and promotes necrosis, thereby inhibiting osteosarcoma growth.

Small cell osteosarcoma in gnathic bones in the maxilla: case report in a pediatric patient

Small cell osteosarcoma (SCOS) is a rare variant of conventional osteosarcoma, characterized by tumor cells of small size and uniform morphology, which can lead to diagnostic confusion with other small cell tumors, requiring a detailed diagnostic approach. The manifestation in a child adds a degree of complexity, as the management of malignant tumours in paediatric patients requires specific considerations to minimize the long-term side effects of oncological treatment and preserve the structural and functional development of the orofacial region. This report concerns an 8-year-old female patient referred to the Oral and Maxillofacial Surgery outpatient clinic with progressive swelling in the right maxillofacial region, initially asymptomatic, but progressing to pain and difficulty chewing. A cone beam computed tomography scan was requested and an incisional biopsy was carried out for histopathological and immunohistochemical analysis, which confirmed the pathological entity. The lesion was then completely resected with a safety margin and the affected area removed to restore functionality and aesthetics. The surgical specimen was sent for further histopathological analysis, which confirmed the diagnosis of SCOS. Detailed immunohistochemical analysis was crucial to the diagnosis, and a comprehensive surgical approach was indicated given the aggressive behavior of the lesion. This report emphasizes the importance of an integrated multidisciplinary approach, combining oncology, pathology and oral and maxillofacial surgery.

Advances in CRISPR-Cas technology and its applications: revolutionising precision medicine

CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-associated proteins) has undergone marked advancements since its discovery as an adaptive immune system in bacteria and archaea, emerged as a potent gene-editing tool after the successful engineering of its synthetic guide RNA (sgRNA) toward the targeting of specific DNA sequences with high accuracy. Besides its DNA editing ability, further-developed Cas variants can also edit the epigenome, rendering the CRISPR-Cas system a versatile tool for genome and epigenome manipulation and a pioneering force in precision medicine. This review explores the latest advancements in CRISPR-Cas technology and its therapeutic and biomedical applications, highlighting its transformative impact on precision medicine. Moreover, the current status of CRISPR therapeutics in clinical trials is discussed. Finally, we address the persisting challenges and prospects of CRISPR-Cas technology.

Feasibility of the inhibitor development for cancer: A systematic approach for drug design

The traditional Chinese medicine (TCM) bupleurum-ginger-licorice formula presents significant anti-cancer effects, but its active ingredients and inhibitory mechanism remain unclear. In this work, the core effective ingredient quercetin and its signal transducer and activator of transcription 3 (Stat3) receptor both were identified by network pharmacology. Quercetin is a low-toxicity, non-carcinogenic flavonoid with antioxidant, anti-inflammatory and anticancer activities, which is widely distributed in edible plants. Stat3 can bind to specific DNA response elements and serves as a transcription factor to promote the translation of some invasion/migration-related target genes, considered as a potential anticancer target. Here, molecular docking and molecular dynamics (MD) simulation both were used to explore molecular recognition of quercetin with Stat3. The results show that quercetin impairs DNA transcription efficiency by hindering Stat3 dimerization, partially destroying DNA conformation. Specifically, when the ligand occupies the SH2 cavity of the enzyme, spatial rejection is not conductive to phosphokinase binding. It indirectly prevents the phosphorylation of Y705 and the formation of Stat3 dimer. When the inhibitor binds to the DT1005 position, it obviously shortens the distance between DNA and DBD, enhances their binding capacity, and thereby reduces the degree of freedom required for transcription. This work not only provides the binding modes between Stat3 and quercetin, but also contributes to the optimization and design of such anti-cancer inhibitors.

Drug development advances in human genetics-based targets

Drug development is a long and costly process, with a high degree of uncertainty from the identification of a drug target to its market launch. Targeted drugs supported by human genetic evidence are expected to enter phase II/III clinical trials or be approved for marketing more quickly, speeding up the drug development process. Currently, genetic data and technologies such as genome-wide association studies (GWAS), whole-exome sequencing (WES), and whole-genome sequencing (WGS) have identified and validated many potential molecular targets associated with diseases. This review describes the structure, molecular biology, and drug development of human genetics-based validated beneficial loss-of-function (LOF) mutation targets (target mutations that reduce disease incidence) over the past decade. The feasibility of eight beneficial LOF mutation targets (PCSK9, ANGPTL3, ASGR1, HSD17B13, KHK, CIDEB, GPR75, and INHBE) as targets for drug discovery is mainly emphasized, and their research prospects and challenges are discussed. In conclusion, we expect that this review will inspire more researchers to use human genetics and genomics to support the discovery of novel therapeutic drugs and the direction of clinical development, which will contribute to the development of new drug discovery and drug repurposing.

Identification of therapeutic targets and prognostic biomarkers in the Siglec family of genes in tumor immune microenvironment of sarcoma

Sarcomas (SARC) are a highly heterogeneous cancer type that is prone to recurrence and metastasis. Numerous studies have confirmed that Siglecs are involved in immune signaling and play a key role in regulating immune responses in inflammatory diseases and various cancers. However, studies that systematically explore the therapeutic and prognostic value of Siglecs in SARC patients are very limited. The online databases GEPIA, UALCAN, TIMER, The Kaplan-Meier Plotter, GeneMANIA, cBioPortal, and STING were used in this study. IHC staining was performed on the collected patient tissues, and clinical data were statistically analyzed. The transcript levels of most Siglec family members showed a high expression pattern in SARC. Compared with normal tissues, Siglec-5, Siglec-10, and Siglec-12 were abnormally highly expressed in tumor tissues. Importantly, Siglec-15 was significantly associated with poor prognosis. Functional enrichment analysis showed that the Siglec family was mainly enriched in hematopoietic cell lineages. The genes associated with molecular mutations in the Siglec family were mainly TP53 and MUC16, among which Siglec-2 and Siglec-15 were significantly associated with the survival of patients. The expression levels of all Siglec family members were significantly correlated with various types of immune cells (B cells, CD8 + T cells, CD4 + T cells, macrophages, neutrophils and dendritic cells). Furthermore, a significant correlation was found between the somatic copy number changes of all Siglec molecules and the abundance of immune infiltrates. Our study paints a promising vision for the development of immunotherapy drugs and the construction of prognostic stratification models by investigating the therapeutic and prognostic potential of the Siglec family for SARC.

Exosome-mediated miR-144-3p promotes ferroptosis to inhibit osteosarcoma proliferation, migration, and invasion through regulating ZEB1

BACKGROUND

Osteosarcoma (OS) is the most prevalent orthopedic malignancy with a dismal prognosis. The high iron absorption rate in OS cells of patients suggests that ferroptosis may be related to the progression of OS, but its potential molecular regulatory role is still unclear. Based on the ability to couple with exosomes for targeted delivery of signals, exosome-derived micro ribonucleic acids (miRNAs) can potentially serve as diagnostic biomarkers for OS.

METHODS

We identified ferroptosis-related miRNAs and messenger ribonucleic acids(mRNAs) in OS using bioinformatics analysis and performed survival analysis. Then we measured miRNA expression levels through exosome microarray sequencing, and used RT-qPCR and IHC to verify the expression level of miR-144-3p and ZEB1. Stable gene expression cell lines were fabricated for in vitro experiments. Cell viability, migration and invasion were determined by CCK-8 and transwell experiment. Use the corresponding reagent kit to detect GSH/GSSG ratio, Fe²⁺ level, MDA level and ROS level, and measure the expression levels of GPX4, ACSL4 and xCT through RT-qPCR and WB. We also constructed nude mice model for in vivo experiments. Finally, the stability of the miRNA/mRNA axis was verified through functional rescue experiments.

RESULTS

Low expression of miR-144-3p and high expression of ZEB1 in OS cell lines and tissues was observed. Overexpression of miR-144-3p can promote ferroptosis, reduce the survival ability of OS cells, and prevent the progression of OS. In addition, overexpression of miR-144-3p can downregulate the expression of ZEB1 in cell lines and nude mice. Knockdown of miR-144-3p has the opposite effect. The functional rescue experiment validated that miR-144-3p can regulate downstream ZEB1, and participates in the occurrence and development of OS by interfering with redox homeostasis and iron metabolism.

CONCLUSIONS

MiR-144-3p can induce the occurrence of ferroptosis by negatively regulating the expression of ZEB1, thereby inhibiting the proliferation, migration, and invasion of OS cells.

Self-Renewal and Pluripotency in Osteosarcoma Stem Cells' Chemoresistance: Notch, Hedgehog, and Wnt/β-Catenin Interplay with Embryonic Markers

Osteosarcoma is a highly malignant bone tumor derived from mesenchymal cells that contains self-renewing cancer stem cells (CSCs), which are responsible for tumor progression and chemotherapy resistance. Understanding the signaling pathways that regulate CSC self-renewal and survival is crucial for developing effective therapies. The Notch, Hedgehog, and Wnt/β-Catenin developmental pathways, which are essential for self-renewal and differentiation of normal stem cells, have been identified as important regulators of osteosarcoma CSCs and also in the resistance to anticancer therapies. Targeting these pathways and their interactions with embryonic markers and the tumor microenvironment may be a promising therapeutic strategy to overcome chemoresistance and improve the prognosis for osteosarcoma patients. This review focuses on the role of Notch, Hedgehog, and Wnt/β-Catenin signaling in regulating CSC self-renewal, pluripotency, and chemoresistance, and their potential as targets for anti-cancer therapies. We also discuss the relevance of embryonic markers, including SOX-2, Oct-4, NANOG, and KLF4, in osteosarcoma CSCs and their association with the aforementioned signaling pathways in overcoming drug resistance.

Targeting RNA Polymerase I Transcription Activity in Osteosarcoma: Pre-Clinical Molecular and Animal Treatment Studies

The survival rate of patients with osteosarcoma (OS) has not improved over the last 30 years. Mutations in the genes TP53, RB1 and c-Myc frequently occur in OS and enhance RNA Polymerase I (Pol I) activity, thus supporting uncontrolled cancer cell proliferation. We therefore hypothesised that Pol I inhibition may be an effective therapeutic strategy for this aggressive cancer. The Pol I inhibitor CX-5461 has demonstrated therapeutic efficacy in different cancers in pre-clinical and phase I clinical trials; thus, the effects were determined on ten human OS cell lines. Following characterisation using genome profiling and Western blotting, RNA Pol I activity, cell proliferation and cell cycle progression were evaluated in vitro, and the growth of TP53 wild-type and mutant tumours was measured in a murine allograft model and in two human xenograft OS models. CX-5461 treatment resulted in reduced ribosomal DNA (rDNA) transcription and Growth 2 (G2)-phase cell cycle arrest in all OS cell lines. Additionally, tumour growth in all allograft and xenograft OS models was effectively suppressed without apparent toxicity. Our study demonstrates the efficacy of Pol I inhibition against OS with varying genetic alterations. This study provides pre-clinical evidence to support this novel therapeutic approach in OS.

Targeted therapy for osteosarcoma: a review

BACKGROUND

Osteosarcoma is a common primary malignant tumour of the bone that usually occurs in children and adolescents. It is characterised by difficult treatment, recurrence and metastasis, and poor prognosis. Currently, the treatment of osteosarcoma is mainly based on surgery and auxiliary chemotherapy. However, for recurrent and some primary osteosarcoma cases, owing to the rapid progression of disease and chemotherapy resistance, the effects of chemotherapy are poor. With the rapid development of tumour-targeted therapy, molecular-targeted therapy for osteosarcoma has shown promise.

PURPOSE

In this paper, we review the molecular mechanisms, related targets, and clinical applications of targeted osteosarcoma therapy. In doing this, we provide a summary of recent literature on the characteristics of targeted osteosarcoma therapy, the advantages of its clinical application, and development of targeted therapy in future. We aim to provide new insights into the treatment of osteosarcoma.

CONCLUSION

Targeted therapy shows potential in the treatment of osteosarcoma and may offer an important means of precise and personalised treatment in the future, but drug resistance and adverse effects may limit its application.

Identification of therapeutic targets for osteosarcoma by integrating single-cell RNA sequencing and network pharmacology

Background: Osteosarcoma (OS) is a common primary tumor with extensive heterogeneity. In this study, we used single-cell RNA sequencing (scRNA-seq) and network pharmacology to analyze effective targets for Osteosarcoma treatment. Methods: The cell heterogeneity of the Osteosarcoma single-cell dataset GSE162454 was analyzed using the Seurat package. The bulk-RNA transcriptome dataset GSE36001 was downloaded and analyzed using the CIBERSORT algorithm. The key targets for OS therapy were determined using Pearson's correlation analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed on key targets. The DeepDR algorithm was used to predict potential drugs for Osteosarcoma treatment. Molecular docking analysis was performed to verify the binding abilities of the predicted drugs and key targets. qRT-PCR assay was used to detect the expression of key targets in osteoblasts and OS cells. Results: A total of 21 cell clusters were obtained based on the GSE162454 dataset, which were labeled as eight cell types by marker gene tagging. Four cell types (B cells, cancer-associated fibroblasts (CAFs), endothelial cells, and plasmocytes) were identified in Osteosarcoma and normal tissues, based on differences in cell abundance. In total, 17 key targets were identified by Pearson's correlation analysis. GO and KEGG analysis showed that these 17 genes were associated with immune regulation pathways. Molecular docking analysis showed that RUNX2, OMD, and CD4 all bound well to vincristine, dexamethasone, and vinblastine. The expression of CD4, OMD, and JUN was decreased in Osteosarcoma cells compared with osteoblasts, whereas RUNX2 and COL9A3 expression was increased. Conclusion: We identified five key targets (CD4, RUNX2, OMD, COL9A3, and JUN) that are associated with Osteosarcoma progression. Vincristine, dexamethasone, and vinblastine may form a promising drug-target pair with RUNX2, OMD, and CD4 for Osteosarcoma treatment.

Ten Years of CRISPRing Cancers In Vitro

Cell lines have always constituted a good investigation tool for cancer research, allowing scientists to understand the basic mechanisms underlying the complex network of phenomena peculiar to the transforming path from a healthy to cancerous cell. The introduction of CRISPR in everyday laboratory activity and its relative affordability greatly expanded the bench lab weaponry in the daily attempt to better understand tumor biology with the final aim to mitigate cancer's impact in our lives. In this review, we aim to report how this genome editing technique affected in the in vitro modeling of different aspects of tumor biology, its several declinations, and analyze the advantages and drawbacks of each of them.

Depletion of R270C Mutant p53 in Osteosarcoma Attenuates Cell Growth but Does Not Prevent Invasion and Metastasis In Vivo

Novel therapeutic targets are needed to better treat osteosarcoma, which is the most common bone malignancy. We previously developed mouse osteosarcoma cells, designated AX (accelerated bone formation) cells from bone marrow stromal cells. AX cells harbor both wild-type and mutant forms of p53 (R270C in the DNA-binding domain, which is equivalent to human R273C). In this study, we showed that mutant p53 did not suppress the transcriptional activation function of wild-type p53 in AX cells. Notably, AXT cells, which are cells derived from tumors originating from AX cells, lost wild-type p53 expression, were devoid of the intact transcription activation function, and were resistant to doxorubicin. ChIP-seq analyses revealed that this mutant form of p53 bound to chromatin in the vicinity of the transcription start sites of various genes but exhibited a different binding profile from wild-type p53. The knockout of mutant p53 in AX and AXT cells by CRISPR-Cas9 attenuated tumor growth but did not affect the invasion of these cells. In addition, depletion of mutant p53 did not prevent metastasis in vivo. Therefore, the therapeutic potency targeting R270C (equivalent to human R273C) mutant p53 is limited in osteosarcoma. However, considering the heterogeneous nature of osteosarcoma, it is important to further evaluate the biological and clinical significance of mutant p53 in various cases.

DNAJA1- and conformational mutant p53-dependent inhibition of cancer cell migration by a novel compound identified through a virtual screen

Cancers are frequently addicted to oncogenic missense mutant p53 (mutp53). DNAJA1, a member of heat shock protein 40 (HSP40), also known as J-domain proteins (JDPs), plays a crucial role in the stabilization and oncogenic activity of misfolded or conformational mutp53 by binding to and preventing mutp53 from proteasomal degradation. However, strategies to deplete mutp53 are not well-established, and no HSP40/JDPs inhibitors are clinically available. To identify compounds that bind to DNAJA1 and induce mutp53 degradation, we performed an in silico docking study of ~10 million of compounds from the ZINC database for the J-domain of DNAJA1. A compound 7-3 was identified, and its analogue A11 effectively reduced the levels of DNAJA1 and conformational mutp53 with minimal effects on the levels of wild-type p53 and DNA-contact mutp53. A11 suppressed migration and filopodia formation in a manner dependent on DNAJA1 and conformational mutp53. A mutant DNAJA1 with alanine mutations at predicted amino acids (tyrosine 7, lysine 44, and glutamine 47) failed to bind to A11. Cells expressing the mutant DNAJA1 became insensitive to A11-mediated depletion of DNAJA1 and mutp53 as well as A11-mediated inhibition of cell migration. Thus, A11 is the first HSP40/JDP inhibitor that has not been previously characterized for depleting DNAJA1 and subsequently conformational mutp53, leading to inhibition of cancer cell migration. A11 can be exploited for a novel treatment against cancers expressing conformational mutp53.

Non-coding RNAs as potential biomarkers in osteosarcoma

Osteosarcoma (OS) is a primary solid malignant tumor that occurs most frequently in the metaphysis of long bones. More likely to happen to children and adolescents. OS has high mortality and disability rate. However, the etiology and pathogenesis of OS have not been fully understood till now. Due to the lack of effective biomarkers, OS cannot be precisely detected in the early stage. With the application of next-generation and high-throughput sequencing, more and more abnormally expressed non-coding RNAs(ncRNAs) have been identified in OS. Growing evidences have suggested the ncRNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), have played an important role in the tumorigenesis and progression of OS. Thus, they can be served as novel biomarkers for diagnosis, treatment and prognosis. This review summarized the application of ncRNA as biomarkers in OS in detail, and discussed the limitation and future improvement of the potential biomarkers.

Genome Editing Approaches with CRISPR/Cas9 for Cancer Treatment: Critical Appraisal of Preclinical and Clinical Utility, Challenges, and Future Research

The increasing burden on human malignant diseases became a major concern for healthcare practitioners, that must deal with tumor relapse and the inability to efficiently treat metastasis, in addition to side effects. Throughout the decades, many therapeutic strategies have been employed to improve the clinical outcomes of cancer patients and great efforts have been made to develop more efficient and targeted medicines. The malignant cell is characterized by genetic and epigenetic modifications, therefore targeting those specific drivers of carcinogenesis is highly desirable. Among the genome editing technologies, CRISPR/Cas9 stood as a promising candidate for cancer treatment alternatives, due to its low complexity design. First described as a defense mechanism of bacteria against invading foreign DNA, later it was shown that CRISPR components can be engineered to target specific DNA sequences in a test tube, a discovery that was awarded later with the Nobel Prize in chemistry for its rapid expansion as a reliable genome editing tool in many fields of research, including medicine. The present paper aims of describing CRISPR/Cas9 potential targets for malignant disorders, and the approaches used for achieving this goal. Aside from preclinical studies, we also present the clinical trials that use CRISPR-based technology for therapeutic purposes of cancer. Finally, a summary of the presented studies adds a more focused view of the therapeutic value CRISPR/Cas9 holds and the associated shortcomings.

Colchicine as a novel drug for the treatment of osteosarcoma through drug repositioning based on an FDA drug library

Background

Colchicine is a traditional medication that is currently approved to treat gout and familial Mediterranean fever (FMF). However, colchicine has a wide range of anti-inflammatory activities, and several studies have indicated that it may be useful in a variety of other conditions, such as rheumatic disease, cardiac disease, and cancer. Osteosarcoma, the most common type of bone sarcoma, is derived from primitive bone-forming mesenchymal cells. In this study, we investigated whether colchicine could be used to treat osteosarcoma through the regulation of cell cycle signaling.

Methods

Two human osteosarcoma cell lines, U2OS and Saos-2, were used. A clonogenic assay was used to determine the antiproliferative effects of colchicine on osteosarcoma cells. Reactive oxygen species (ROS) production and apoptosis were measured by flow cytometry. Migration and invasion assays were performed to investigate the inhibitory effects of colchicine. The signaling pathways related to colchicine treatment were verified by GO biological process (GOBP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses.

Results

Colchicine was selected as the lead compound based on the results of initial screening and cell viability assays conducted in Saos-2 and U2Os cells. Colchicine reduced the viability of Saos-2 and U2OS cells in a concentration-dependent manner. It also significantly inhibited colony-forming ability and induced ROS production and apoptosis. It also inhibited the migration and invasion of both Saos-2 and U2OS cells. GOBP and KEGG enrichment analyses indicated the involvement of microtubule-based processes and cancer-related pathways.

Conclusions

These findings suggest that colchicine has therapeutic potential in osteosarcoma.

Misleading Morphologic and Phenotypic Features (Transdifferentiation) in Solitary Fibrous Tumor of the Head and Neck: Report of 3 Cases and Review of the Literature

Solitary fibrous tumor (SFT) is a rare fibroblastic neoplasm with potentially malignant behavior that may develop in any anatomic site and may involve the head and neck (H&N) region as well. Although typical SFT has a relatively characteristic morphology, its morphologic spectrum is extraordinarily broad and also includes rare cases with dedifferentiation or transdifferentiation which result in aberrant morphologic and/or immunohistochemical features. However, since virtually all cases are molecularly characterized by NAB2::STAT6 gene fusions, molecular genetic methods or STAT6 immunohistochemistry can be effectively used in confirming the diagnosis. Herein, we report 3 diagnostically challenging H&N SFT cases with an unusual morphology and/or phenotypes closely mimicking other well-known H&N entities. The tumors originated in the oral minor salivary glands, the base of the tongue, and sinonasal tract and closely resembled hyalinizing clear cell carcinoma of the salivary gland, adenocarcinoma not otherwise specified and biphenotypic sinonasal sarcoma, respectively. All cases were positive for cytokeratins, variably expressed S100 protein, showed diffuse nuclear STAT6 positivity, and harbored NAB2::STAT6 gene fusions.

CRISPR/Cas9 gene editing: a new approach for overcoming drug resistance in cancer

The CRISPR/Cas9 system is an RNA-based adaptive immune system in bacteria and archaea. Various studies have shown that it is possible to target a wide range of human genes and treat some human diseases, including cancers, by the CRISPR/Cas9 system. In fact, CRISPR/Cas9 gene editing is one of the most efficient genome manipulation techniques. Studies have shown that CRISPR/Cas9 technology, in addition to having the potential to be used as a new therapeutic approach in the treatment of cancers, can also be used to enhance the effectiveness of existing treatments. Undoubtedly, the issue of drug resistance is one of the main obstacles in the treatment of cancers. Cancer cells resist anticancer drugs by a variety of mechanisms, such as enhancing anticancer drugs efflux, enhancing DNA repair, enhancing stemness, and attenuating apoptosis. Mutations in some proteins of different cellular signaling pathways are associated with these events and drug resistance. Recent studies have shown that the CRISPR/Cas9 technique can be used to target important genes involved in these mechanisms, thereby increasing the effectiveness of anticancer drugs. In this review article, studies related to the applications of this technique in overcoming drug resistance in cancer cells will be reviewed. In addition, we will give a brief overview of the limitations of the CRISP/Cas9 gene-editing technique.

Noncanonical roles of p53 in cancer stemness and their implications in sarcomas

Impairment of the prominent tumor suppressor p53, well known for its canonical role as the "guardian of the genome", is found in almost half of human cancers. More recently, p53 has been suggested to be a crucial regulator of stemness, orchestrating the differentiation of embryonal and adult stem cells, suppressing reprogramming into induced pluripotent stem cells, or inhibiting cancer stemness (i.e., cancer stem cells, CSCs), which underlies the development of therapy-resistant tumors. This review addresses these noncanonical roles of p53 and their implications in sarcoma initiation and progression. Indeed, dysregulation of p53 family proteins is a common event in sarcomas and is associated with poor survival. Additionally, emerging studies have demonstrated that loss of wild-type p53 activity hinders the terminal differentiation of mesenchymal stem cells and leads to the development of aggressive sarcomas. This review summarizes recent findings on the roles of aberrant p53 in sarcoma development and stemness and further describes therapeutic approaches to restore normal p53 activity as a promising anti-CSC strategy to treat refractory sarcomas.

Network Pharmacology Prediction: The Possible Mechanisms of Cinobufotalin against Osteosarcoma

OBJECTIVE

To explore the active compounds and targets of cinobufotalin (huachansu) compared with the osteosarcoma genes to obtain the potential therapeutic targets and pharmacological mechanisms of action of cinobufotalin on osteosarcoma through network pharmacology.

METHODS

The composition of cinobufotalin was searched by literature retrieval, and the target was selected from the CTD and TCMSP databases. The osteosarcoma genes, found from the GeneCards, OMIM, and other databases, were compared with the cinobufotalin targets to obtain potential therapeutic targets. The protein-protein interaction (PPI) network of potential therapeutic targets, constructed through the STRING database, was inputted into Cytoscape software to calculate the hub genes, using the NetworkAnalyzer. The hub genes were inputted into the Kaplan-Meier Plotter online database for exploring the survival curve. Functional enrichment analysis was identified using the DAVID database.

RESULTS

28 main active compounds of cinobufotalin were explored, including bufalin, adenosine, oleic acid, and cinobufagin. 128 potential therapeutic targets on osteosarcoma are confirmed among 184 therapeutic targets form cinobufotalin. The hub genes included TP53, ACTB, AKT1, MYC, CASP3, JUN, TNF, VEGFA, HSP90AA1, and STAT3. Among the hub genes, TP53, ACTB, MYC, TNF, VEGFA, and STAT3 affect the patient survival prognosis of sarcoma. Through function enrichment analysis, it is found that the main mechanisms of cinobufotalin on osteosarcoma include promoting sarcoma apoptosis, regulating the cell cycle, and inhibiting proliferation and differentiation.

CONCLUSION

The possible mechanisms of cinobufotalin against osteosarcoma are preliminarily predicted through network pharmacology, and further experiments are needed to prove these predictions.

Optimizing sgRNA to Improve CRISPR/Cas9 Knockout Efficiency: Special Focus on Human and Animal Cell

During recent years, clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) technologies have been noticed as a rapidly evolving tool to deliver a possibility for modifying target sequence expression and function. The CRISPR/Cas9 tool is currently being used to treat a myriad of human disorders, ranging from genetic diseases and infections to cancers. Preliminary reports have shown that CRISPR technology could result in valued consequences for the treatment of Duchenne muscular dystrophy (DMD), cystic fibrosis (CF), β-thalassemia, Huntington's diseases (HD), etc. Nonetheless, high rates of off-target effects may hinder its application in clinics. Thereby, recent studies have focused on the finding of the novel strategies to ameliorate these off-target effects and thereby lead to a high rate of fidelity and accuracy in human, animals, prokaryotes, and also plants. Meanwhile, there is clear evidence indicating that the design of the specific sgRNA with high efficiency is of paramount importance. Correspondingly, elucidation of the principal parameters that contributed to determining the sgRNA efficiencies is a prerequisite. Herein, we will deliver an overview regarding the therapeutic application of CRISPR technology to treat human disorders. More importantly, we will discuss the potent influential parameters (e.g., sgRNA structure and feature) implicated in affecting the sgRNA efficacy in CRISPR/Cas9 technology, with special concentration on human and animal studies.

Nanotechnology-based delivery of CRISPR/Cas9 for cancer treatment

CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats-associated protein 9) is a potent technology for gene-editing. Owing to its high specificity and efficiency, CRISPR/Cas9 is extensity used for human diseases treatment, especially for cancer, which involves multiple genetic alterations. Different concepts of cancer treatment by CRISPR/Cas9 are established. However, significant challenges remain for its clinical applications. The greatest challenge for CRISPR/Cas9 therapy is how to safely and efficiently deliver it to target sites in vivo. Nanotechnology has greatly contributed to cancer drug delivery. Here, we present the action mechanisms of CRISPR/Cas9, its application in cancer therapy and especially focus on the nanotechnology-based delivery of CRISPR/Cas9 for cancer gene editing and immunotherapy to pave the way for its clinical translation. We detail the difficult barriers for CRISIR/Cas9 delivery in vivo and discuss the relative solutions for encapsulation, target delivery, controlled release, cellular internalization, and endosomal escape.

TP53 in Biology and Treatment of Osteosarcoma

The TP53 gene is mutated in 50% of human tumors. Oncogenic functions of mutant TP53 maintain tumor cell proliferation and tumor growth also in osteosarcomas. We collected data on TP53 mutations in patients to indicate which are more common and describe their role in in vitro and animal models. We also describe animal models with TP53 dysfunction, which provide a good platform for testing the potential therapeutic approaches. Finally, we have indicated a whole range of pharmacological compounds that modulate the action of p53, stabilize its mutated versions or lead to its degradation, cause silencing or, on the contrary, induce the expression of its functional version in genetic therapy. Although many of the described therapies are at the preclinical testing stage, they offer hope for a change in the approach to osteosarcoma treatment based on TP53 targeting in the future.

Applications of CRISPR/Cas9 in the research of malignant musculoskeletal tumors

Background

Malignant tumors of the musculoskeletal system, especially osteosarcoma, Ewing sarcoma and rhabdomyosarcoma, pose a major threat to the lives and health of adolescents and children. Current treatments for musculoskeletal tumors mainly include surgery, chemotherapy, and radiotherapy. The problems of chemotherapy resistance, poor long-term outcome of radiotherapy, and the inherent toxicity and side effects of chemical drugs make it extremely urgent to seek new treatment strategies.

Main text

As a potent gene editing tool, the rapid development of CRISPR/Cas9 technology in recent years has prompted scientists to apply it to the study of musculoskeletal tumors. This review summarizes the application of CRISPR/Cas9 technology for the treatment of malignant musculoskeletal tumors, focusing on its essential role in the field of basic research.

Conclusion

CRISPR, has demonstrated strong efficacy in targeting tumor-related genes, and its future application in the clinical treatment of musculoskeletal tumors is promising.

Single-cell RNA landscape of intratumoral heterogeneity and immunosuppressive microenvironment in advanced osteosarcoma

Osteosarcoma is the most frequent primary bone tumor with poor prognosis. Through RNA-sequencing of 100,987 individual cells from 7 primary, 2 recurrent, and 2 lung metastatic osteosarcoma lesions, 11 major cell clusters are identified based on unbiased clustering of gene expression profiles and canonical markers. The transcriptomic properties, regulators and dynamics of osteosarcoma malignant cells together with their tumor microenvironment particularly stromal and immune cells are characterized. The transdifferentiation of malignant osteoblastic cells from malignant chondroblastic cells is revealed by analyses of inferred copy-number variation and trajectory. A proinflammatory FABP4+ macrophages infiltration is noticed in lung metastatic osteosarcoma lesions. Lower osteoclasts infiltration is observed in chondroblastic, recurrent and lung metastatic osteosarcoma lesions compared to primary osteoblastic osteosarcoma lesions. Importantly, TIGIT blockade enhances the cytotoxicity effects of the primary CD3+ T cells with high proportion of TIGIT+ cells against osteosarcoma. These results present a single-cell atlas, explore intratumor heterogeneity, and provide potential therapeutic targets for osteosarcoma.

Cellular plasticity and drug resistance in sarcoma

Sarcomas, originating from mesenchymal progenitor stem cells, are a group of rare malignant tumors with poor prognosis. Wide surgical resection, chemotherapy, and radiotherapy are the most common sarcoma treatments. However, sarcomas' response rates to chemotherapy are quite low and sarcoma cells can have intrinsic or acquired resistance after treatment with chemotherapeutics drugs, leading to the development of multi-drug resistance (MDR). Cancer cellular plasticity plays pivotal roles in cancer initiation, progression, therapy resistance and cancer relapse. Moreover, cancer cellular plasticity can be regulated by a multitude of factors, such as genetic and epigenetic alterations, tumor microenvironment (TME) or selective pressure imposed by treatment. Recent studies have demonstrated that cellular plasticity is involved in sarcoma progression and chemoresistance. It's essential to understand the molecular mechanisms of cellular plasticity as well as its roles in sarcoma progression and drug resistance. Therefore, this review focuses on the regulatory mechanisms and pathological roles of these diverse cellular plasticity programs in sarcoma. Additionally, we propose cellular plasticity as novel therapeutic targets to reduce sarcoma drug resistance.

Comprehensive bioinformatics analysis of the TP53 signaling pathway in Wilms' tumor

Background

Differential expression of tumor protein 53 (TP53, or p53) has been observed in multiple cancers. However, the expression levels and prognostic role of TP53 signaling pathway genes in Wilms' tumor (WT) have yet to be fully explored.

Methods

The expression levels of TP53 signaling pathway genes including TP53, mouse double minute 2 (MDM2), mouse double minute 4 (MDM4), cyclin-dependent kinase 2A (CDKN2A), cyclin-dependent kinase 2B (CDKN2B), and tumor suppressor p53-binding protein 1 (TP53BP1) in WT were analyzed using the Oncomine database. Aberration types, co-mutations, mutation locations, signaling pathways, and the prognostic role of TP53 in WT were investigated using cBioPortal. MicroRNA (miRNA) and transcription factor (TF) targets were identified with miRTarBase, miWalk, and ChIP-X Enrichment Analysis 3 (CheA3), respectively. A protein-protein network was constructed using GeneMANIA. The expression of TP53 signaling genes were confirmed in WT samples and normal kidney tissues using the Human Protein Atlas (HPA). Cancer Therapeutics Response Portal (CTRP) was used to analyze the small molecules potentially targeting TP53.

Results

TP53 was significantly expressed in the Cutcliffe Renal (P=0.010), but not in the Yusenko Renal (P=0.094). Meanwhile, MDM2 was significantly overexpressed in the Yusenko Renal (P=0.058), but not in the Cutcliffe Renal (P=0.058). The expression levels of MDM4 no significant difference between the tumor and normal tissue samples. The most common TP53 alteration was missense and the proportion of TP53 pathway-related mutations was 2.3%. Co-expressed genes included ZNF609 (zinc finger protein 609), WRAP53 (WD40-encoding RNA antisense to p53), CNOT2 (CC chemokine receptor 4-negative regulator of transcription 2), and CDH13 (cadherin 13). TP53 alterations indicated poor prognosis of WT (P=1.051e-4). The regulators of the TP53 pathway included miR-485-5p and TFs NR2F2 and KDM5B. The functions of TP53 signaling pathway were signal transduction in response to DNA damage and regulate the cell cycle. The small molecules targeting TP53 included PRIMA-1, RITA, SJ-172550, and SCH-529074.

Conclusions

TP53 was found to be differentially expressed in WT tissues. TP53 mutations indicated poor outcomes of WT. Therefore, pifithrin-mu, PRIMA-1, RITA, SJ-172550, and SCH-529074 could be used in combination with traditional chemotherapy to treat WT.

Identification of potential crucial genes and key pathways in osteosarcoma

Background

The aim of this study is to identify the potential pathogenic and metastasis-related differentially expressed genes (DEGs) in osteosarcoma through bioinformatic analysis of Gene Expression Omnibus (GEO) database.

Results

Gene expression profiles of GSE14359, GSE16088, and GSE33383, in total 112 osteosarcoma tissue samples and 7 osteoblasts, were analyzed. Seventy-four normal-primary DEGs (NPDEGs) and 764 primary-metastatic DEGs (PMDEGs) were screened. VAMP8, A2M, HLA-DRA, SPARCL1, HLA-DQA1, APOC1 and AQP1 were identified continuously upregulating during the oncogenesis and metastasis of osteosarcoma. The enriched functions and pathways of NPDEGs include procession and presentation of antigens, activation of MHC class II receptors and phagocytosis. The enriched functions and pathways of PMDEGs include mitotic nuclear division, cell adhesion molecules (CAMs) and focal adhesion. With protein-protein interaction (PPI) network analyzed by Molecular Complex Detection (MCODE) plug-in of Cytoscape software, one hub NPDEG (HLA-DRA) and 7 hub PMDEGs (CDK1, CDK20, CCNB1, MTIF2, MRPS7, VEGFA and EGF) were eventually selected, and the most significant pathways in NPDEGs module and PMDEGs module were enriched in the procession and presentation of exogenous peptide antigen via MHC class II and the nuclear division, respectively.

Conclusions

By integrated bioinformatic analysis, numerous DEGs related to osteosarcoma were screened, and the hub DEGs identified in this study are possibly part of the potential biomarkers for osteosarcoma. However, further experimental studies are still necessary to elucidate the biological function and mechanism of these genes.

Applications of CRISPR for musculoskeletal research

The ability to edit DNA at the nucleotide level using clustered regularly interspaced short palindromic repeats (CRISPR) systems is a relatively new investigative tool that is revolutionizing the analysis of many aspects of human health and disease, including orthopaedic disease. CRISPR, adapted for mammalian cell genome editing from a bacterial defence system, has been shown to be a flexible, programmable, scalable, and easy-to-use gene editing tool. Recent improvements increase the functionality of CRISPR through the engineering of specific elements of CRISPR systems, the discovery of new, naturally occurring CRISPR molecules, and modifications that take CRISPR beyond gene editing to the regulation of gene transcription and the manipulation of RNA. Here, the basics of CRISPR genome editing will be reviewed, including a description of how it has transformed some aspects of molecular musculoskeletal research, and will conclude by speculating what the future holds for the use of CRISPR-related treatments and therapies in clinical orthopaedic practice.

Cite this article: Bone Joint Res 2020;9(7):351–359.

Emerging next-generation sequencing-based discoveries for targeted osteosarcoma therapy

Osteosarcoma (OS) is the most common primary bone malignancy and is frequently lethal via metastasis to the lung. While surgical techniques and adjuvant chemotherapies have emerged to combat this deadly cancer, the 5-year survival rate has plateaued over the past four decades. Therapeutic progress has been notably poor because past technologies have not been able to reveal obscured OS biomarkers and targets. With the advent and implementation of large-scale next-generation sequencing (NGS) studies, various somatic mutations and copy number changes involved in OS progression and metastasis have surfaced. These findings have significantly expanded the amount of genome-informed pathways and candidate genes suitable for targeting in pre-clinical models. Furthermore, NGS analyses comparing primary and matched pulmonary metastatic tumor tissues have catalogued previously unknown prognostic biomarkers in OS. In this review, we delineate the most recent findings in NGS for OS therapy and how this technology has advanced personalized therapy.

Recent advances in bone-targeted therapy

The coordination between bone resorption and bone formation plays an essential role in keeping the mass and microstructure integrity of the bone in a steady state. However, this balance can be disturbed in many pathological conditions of the bone. Nowadays, the classical modalities for treating bone-related disorders are being challenged by severe obstacles owing to low tissue selectivity and considerable safety concerns. Moreover, as a highly mineralized tissue, the bone shows innate rigidity, low permeability, and reduced blood flow, features that further hinder the effective treatment of bone diseases. With the development of bone biology and precision medicine, one novel concept of bone-targeted therapy appears to be promising, with improved therapeutic efficacy and minimized systematic toxicity. Here we focus on the recent advances in bone-targeted treatment based on the unique biology of bone tissues. We summarize commonly used bone-targeting moieties, with an emphasis on bisphosphonates, tetracyclines, and biomimetic bone-targeting moieties. We also introduce potential bone-targeting strategies aimed at the bone matrix and major cell types in the bone. Based on these bone-targeting moieties and strategies, we discuss the potential applications of targeted therapy to treat bone diseases. We expect that this review will put together useful insights to help with the search for therapeutic efficacy in bone-related conditions.

Cancer testis antigens in sarcoma: Expression, function and immunotherapeutic application

Sarcomas are a group of heterogeneous malignancies of mesenchymal origin. Patient outcomes remain especially grim for those with recurrent or metastatic disease, and current therapeutic strategies have not significantly improved outcomes over the past few decades. This has led to a number of studies assessing novel therapies. Cancer testis antigens (CTAs) are tumor-associated antigens with physiologic expression in the testis and various malignancies, including sarcomas. Genes encoding CTAs include MAGE, NY-ESO-1, PRAME, TRAG-3/CSAGE, and SSX. The importance and function of CTAs in tumorigenesis have gained recognition in recent years. They are also proving as robust diagnostic and prognostic biomarkers. Therapeutically, antigens derived from CTAs are highly recognizable by T lymphocytes and therefore capable of generating a potent antitumor immune response. CTAs are, therefore, promising targets for novel immunotherapies. Here we review the emerging works on expression, function, and immunotherapeutic application of CTAs in sarcoma therapy.