Investigating the synergy of Shikonin and Valproic acid in inducing apoptosis of osteosarcoma cells via ROS-mediated EGR1 expression.

BACKGROUND: Osteosarcoma is the most prevalent malignant bone tumour with a poor prognosis. Shikonin (SHK) is derived from the traditional Chinese medicine Lithospermum that has been extensively studied for its notable anti-tumour effects, including for osteosarcoma. However, its application has certain limitations. Valproic acid (VPA) is a histone deacetylase inhibitor (HDACI) that has recently been employed as an adjunctive therapeutic agent that allows chromatin to assume a more relaxed state, thereby enhancing anti-tumour efficacy. PURPOSE: This study was aimed to investigate the synergistic anti-tumour efficacy of SHK in combination with VPA and elucidate its underlying mechanism. METHODS/STUDY DESIGN: CCK-8 assays were utilized to calculate the combination index. Additional assays, including colony formation, acridine orange/ethidium bromide double fluorescent staining, and flow cytometry, were employed to evaluate the effects on osteosarcoma cells. Wound healing and transwell assays were utilized to assess cell mobility. RNA sequencing, PCR, and Western blot analyses were conducted to uncover the underlying mechanism. Rescue experiments were performed to validate the mechanism of apoptotic induction. The impact of SHK and VPA combination treatment on primary osteosarcoma cells was also assessed. Finally, in vivo experiments were conducted to validate its anti-tumour effects and mechanism. RESULTS: The combination of SHK and VPA synergistically inhibited the proliferation and migration of osteosarcoma cells in vitro and induced apoptosis in these cells. Through a comprehensive analysis involving RNA sequencing, PCR, Western blot, and rescue experiments, we have substantiated our hypothesis that the combination of SHK and VPA induced apoptosis via the ROS-EGR1-Bax axis. Importantly, our in vivo experiments corroborated these findings, demonstrating the potential of the SHK and VPA combination as a promising therapeutic approach for osteosarcoma. CONCLUSION: The combination of SHK and VPA exerted an anti-tumour effect by inducing apoptosis through the ROS-EGR1-Bax pathway. Repurposing the old drug VPA demonstrated its effectiveness as an adjunctive therapeutic agent for SHK, enhancing its anti-tumour efficacy and revealing its potential value. Furthermore, our study expanded the application of natural compounds in the anti-tumour field and overcame some of their limitations through combination therapy. Finally, we enhanced the understanding of the mechanistic pathways linking reactive oxygen species (ROS) accumulation and apoptosis in osteosarcoma cells. Additionally, we elucidated the role of EGR1 in osteosarcoma cells, offering novel strategies and concepts for the treatment of osteosarcoma.

Application of Immune Infiltration Signature and Machine Learning Model in the Differential Diagnosis and Prognosis of Bone-Related Malignancies.

Bone-related malignancies, such as osteosarcoma, Ewing's sarcoma, multiple myeloma, and cancer bone metastases have similar histological context, but they are distinct in origin and biological behavior. We hypothesize that a distinct immune infiltrative microenvironment exists in these four most common malignant bone-associated tumors and can be used for tumor diagnosis and patient prognosis. After sample cleaning, data integration, and batch effect removal, we used 22 publicly available datasets to draw out the tumor immune microenvironment using the ssGSEA algorithm. The diagnostic model was developed using the random forest. Further statistical analysis of the immune microenvironment and clinical data of patients with osteosarcoma and Ewing's sarcoma was carried out. The results suggested significant differences in the microenvironment of bone-related tumors, and the diagnostic accuracy of the model was higher than 97%. Also, high infiltration of multiple immune cells in Ewing's sarcoma was suggestive of poor patient prognosis. Meanwhile, increased infiltration of macrophages and B cells suggested a better prognosis for patients with osteosarcoma, and effector memory CD8 T cells and type 2 T helper cells correlated with patients' chemotherapy responsiveness and tumor metastasis. Our study revealed that the random forest diagnostic model based on immune infiltration can accurately perform the differential diagnosis of bone-related malignancies. The immune microenvironment of osteosarcoma and Ewing's sarcoma has an important impact on patient prognosis. Suppressing the highly inflammatory environment of Ewing's sarcoma and promoting macrophage and B cell infiltration may have good potential to be a novel adjuvant treatment option for osteosarcoma and Ewing's sarcoma.

Recurrence of Giant Cell Tumor of the Spine after Resection: A Report of 10 Cases.

OBJECTIVE: To review the clinical details and further treatments for recurrent spinal giant cell tumors (SGCT), and to analyze the risk factors of recurrence and shed new light on the treatment options and prognosis of recurrent SGCT. METHODS: A retrospective analysis of recurrent SGCT between April 2003 and January 2014 was performed. A total of 10 patients comprising 3 men and 7 women with a mean age of 28.9 years (range, 21-40 years) were included in the study. All complete clinical data, radiographs, CT, MRI, scans and pathological data were reviewed. The tumor locations and the regions involved were evaluated by CT and MRI. The blood supply of the tumors was evaluated by enhanced CT and MRI. The mean follow-up was 81.3 months (range, 35.7-172.1 months). RESULTS: All patients had Enneking stage 3 tumors; 9 (90%) of them had different extents of spinal canal involvement in the primary time period. All patients underwent intralesional resection during their first surgery. Only 1 patient received local adjuvant treatments; no patient underwent selective arterial embolization or used denosumab at that time. Only 1 patient underwent adjuvant radiotherapy postoperatively, and another patient used bisphosphonates. After recurrence, 1 patient was cured using denosumab, and 2 patients' disease was controlled through use of other medical treatments or adjuvant treatments. There were 3 repeated recurrences and 7 repeated surgical procedures were performed in 5 patients. There were 6 intralesional excisions and 1 decompression surgery. The mean relapse-free time after the first surgery was 32.3 months (range, 10.5-62.6 months). The overall mean relapse-free time was 40.2 months (range, 10.5-157 months). No distant metastasis was found in our series. At the final follow-up, 4 patients were disease free, 3 patients' disease was under control, 2 has progressive disease aggravation, while 1 patient died as a result of progression of disease 133.9 months after first surgery. CONCLUSION: Intralesional excision for recurrent spinal giant cell tumors is an effective option that may have satisfactory prognosis. However, the excision and the inactivation of the lesion should be carried out carefully and thoroughly without missing any corners. Early diagnosis of recurrence may be associated with better prognosis. Adjuvant treatments perioperatively and systemic medical treatments can decrease recurrence rates and can have therapeutic effects in the recurrent SGCT.

Zoledronic acid sensitizes rhabdomyosarcoma cells to cytolysis mediated by human γδ T cells.

Rhabdomyosarcoma (RMS) is the most common type of soft-tissue sarcoma in children. Immunotherapy has been proposed as a treatment for this deadly tumor. In the present study, the cytotoxicity of ex vivo expanded γδ T cells on RMS cell lines was evaluated and the molecular interactions involved were investigated. γδ T cells were expanded in vitro using peripheral blood mononuclear cells from 5 healthy donors and were stimulated with zoledronic acid (Zol) and interleukin 2. RMS cell lines RD and A-673 were used as target cells. The cytotoxicity of the γδ T cells against RMS was assessed in vitro and in vivo. γδ T cells were cytotoxic to RMS cells. Importantly, Zol markedly increased their cytotoxic potential. RMS cells treated with Zol-stimulated γδ T cells to produce interferon γ. γδ T cell-mediated cytotoxicity was primarily through the T cell receptor-dependent signaling pathway in blocking studies. Transfer of γδ T cells together with Zol into nude mice induced the regression of RD tumor xenotransplants. The results of the present study provide the rationale for the clinical evaluation of γδ T cells in RMS.

SIRT1 promotes metastasis of human osteosarcoma cells.

Pulmonary metastasis is the leading cause of mortality in patients with osteosarcoma; however, the underlying mechanism remains unclear. The NAD+-dependent deacetylase, sirtuin 1 (SIRT1), has been reported to play a key role in carcinogenesis through deacetylation of important regulatory proteins. Here, we report that SIRT1 promotes osteosarcoma metastasis by regulating the expression of metastatic-associated genes. The SIRT1 protein was significantly upregulated in most primary osteosarcoma tumours, compared with normal tissues, and the SIRT1 expression level may be coupled with metastatic risk in patients with osteosarcoma. Moreover, the results of cell migration and wound-healing assays further suggested that higher expression of SIRT1 promoted invasive activity of osteosarcoma cells. Importantly, downregulating SIRT1 with shRNA inhibited the migration ability of osteosarcoma cells in vitro and suppressed tumour lung metastasis in mice. Finally, a gene expression analysis showed that knockdown of SIRT1 profoundly activated translation of its downstream pathway, particularly at migration and invasion. In summary, high levels of SIRT1 may be a biomarker for a high metastatic rate in osteosarcoma patients; inhibiting SIRT1 could be a potent therapeutic intervention for these patients.

The role of CTLA-4 and PD-1 in anti-tumor immune response and their potential efficacy against osteosarcoma.

Immunotherapy is proved to be a promising therapeutic strategy against human malignancies. Evasion of immune surveillance is considered to be a major factor of malignant progression. Inhibitory receptors, especially CTLA-4 and PD-1, are found to play critical roles in the mediation of anti-tumor immune efficacy. Thus, antibodies targeting these immune checkpoints have emerged as the attractive treatment approaches to those patients with cancer. Osteosarcoma is highly malignant and current treatment remains a challenge, especially for those patients with metastasis. Despite some achievements, the effect of immunotherapy against osteosarcoma is still unsatisfactory. The present review attempts to show the role and mechanism of CTLA-4 and PD-1 in immune response and summarize the recent findings related to the effect of inhibitory receptor antibodies on the immune response against tumors, especially osteosarcoma, and the correlation between PD-1 or/and CTLA-4 expression and outcome of osteosarcoma patients. We further discuss the utilization of the combination therapy against osteosarcoma.

Prognostic role of hypoxia-inducible factor-1 alpha expression in osteosarcoma: a meta-analysis.

BACKGROUND: Hypoxia-inducible factor-1α (HIF-1α) plays an important role in tumor progression and metastasis. A number of studies have investigated the association of HIF-1α with prognosis and clinicopathological characteristics of osteosarcoma but yielded inconsistent results. METHOD: Systematic computerized searches were performed in PubMed, Embase, and Web of Science databases for relevant original articles. The pooled hazard ratios (HRs) and odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated to assess the prognostic value of HIF-1α expression. The standard mean difference was used to analyze the continuous variable. RESULTS: Finally, nine studies comprising 486 patients were subjected to final analysis. Protein expression level of HIF-1α was found to be significantly related to overall survival (HR =3.0; 95% CI: 1.46-6.15), disease-free survival (HR =2.23; 95% CI: 1.26-3.92), pathologic grade (OR =21.33; 95% CI: 4.60-98.88), tumor stage (OR =10.29; 95% CI: 3.55-29.82), chemotherapy response (OR =9.68; 95% CI: 1.87-50.18), metastasis (OR =5.06; 95% CI: 2.87-8.92), and microvessel density (standard mean difference =2.83; 95% CI: 2.28-3.39). CONCLUSION: This meta-analysis revealed that overexpression of HIF-1α is a predictive factor of poor outcomes for osteosarcoma. HIF-1α appeared to play an important role in prognostic evaluation and may be a potential target in antitumoral therapy.

Prognostic Significance of Serum Alkaline Phosphatase Level in Osteosarcoma: A Meta-Analysis of Published Data.

BACKGROUND: Serum alkaline phosphatase (SALP) is commonly elevated in osteosarcoma patients. A number of studies have investigated the prognostic role of SALP level in patients with osteosarcoma but yielded inconsistent results. METHOD: Systematic computerized searches were performed in PubMed, Embase, and Web of Science databases for relevant original articles. The pooled hazard ratios (HRs) and relative risks (RRs) with corresponding confidence intervals (CIs) were calculated to assess the prognostic value of SALP level. RESULTS: Finally, 21 studies comprising 3228 patients were included. Overall, the pooled HRs of SALP suggested that elevated level had an unfavorable impact on osteosarcoma patients' overall survival (OS) (HR = 1.82; 95% CI: 1.61-2.06; p < 0.001) and event-free survival (EFS) (HR = 1.97; 95% CI: 1.61-2.42; p < 0.001). Combined RRs of SALP indicated that elevated level was associated with presence of metastasis at diagnosis (RR = 5.55; 95% CI: 1.61-9.49; p = 0.006). No significantly different results were obtained after stratified by variables of age range, cancer stage, sample size, and geographic region. CONCLUSION: This meta-analysis demonstrated that high SALP level is significantly associated with poor OS or EFS rate and presence of metastasis at diagnosis. SALP level is a convenient and effective biomarker of prognosis for osteosarcoma.

Trastuzumab enhanced the cytotoxicity of Vγ9Vδ2 T cells against zoledronate-sensitized osteosarcoma cells.

Preliminary studies of Vγ9Vδ2 T cells and zoledronate (ZOL) present promising reasons to exploit their immunotherapeutic potential for osteosarcoma treatment (OS). ZOL is a third-generation aminobisphosphonate (ABP) and is well established in the management of cancer-induced bone disease. However, ZOL is characterized by high tropism for bone matrix, and the efficacy of ZOL for sensitizing tumors remains to be optimized. Vγ9Vδ2 T cells are important effectors of antibody-dependent cell-mediated cytotoxicity (ADCC). In this study, we investigated whether Vγ9Vδ2 T cell-mediated killing of ZOL-pretreated OS cells could be increased by the anti-HER-2 monoclonal antibody trastuzumab (TTZ). The cytotoxic activity of Vγ9Vδ2 T cells against osteosarcoma was assessed by an MTS assay in the presence or absence of TTZ. A CD107a assay was used to measure degranulation in cytotoxic Vγ9Vδ2 T cells. Blocking studies were used to determine the effect of relative ligands on Vγ9Vδ2 T cell recognition. TTZ induced an ADCC response in the OS cell line, U2OS; however, it had no effect on another OS cell line HOS with low levels of surface HER2 expression. Although the OS cells pretreated with ZOL for clinically relevant time periods (2hours) stimulated a suboptimal immune response of Vγ9Vδ2 T cells, TTZ could further enhance the cytotoxicity of Vγ9Vδ2 T cells. These results demonstrate that combining TTZ and ZOL significantly increases the cytotoxic potential of Vγ9Vδ2 T cells. This study raises the possibility of utilizing ZOL and TTZ in Vγ9Vδ2 T cell-based immunotherapy for OS.