Analysis of Chemotherapy Dosage and Dosage Intensity and Survival Outcomes of High-Grade Osteosarcoma Patients Younger Than 40 Years

LncRNA EBLN3P attributes methotrexate resistance in osteosarcoma cells through miR-200a-3p/O-GlcNAc transferase pathway

BACKGROUND

Osteosarcoma is highly malignant. The migration, invasion, and chemoresistance contribute to poor prognosis of osteosarcoma. Research reported that endogenous bornavirus-like nucleoprotein 3 pseudogene (EBLN3P) promotes the progression of osteosarcoma.

METHODS

In this study, the expression of EBLN3P in osteosarcoma tissue with different methotrexate (MTX) treatment responses was measured. Osteosarcoma cell lines with MTX resistance were constructed, and bioinformatic analysis was performed to explore the potential involved targets and pathways.

RESULTS

Higher EBLN3P was associated with MTX resistance. Downregulation of LncEBLN3P decreased the MTX resistance of osteosarcoma cells by sponging miR-200a-3p, an important microRNA that affects epithelial-mesenchymal transition (EMT). The decreased miR-200a-3p resulted in the upregulation of its target gene O-GlcNAc transferase (OGT), which in turn promoted the EMT process of osteosarcoma cells. Further analysis confirmed that the loss of OGT and over-expression of miR-200a-3p could partly abolish the MTX resistance induced by LncEBLN3P.

CONCLUSION

LncEBLN3P is upregulated in osteosarcoma and increases the MTX resistance in osteosarcoma cells through downregulating miR-200a-3p, which in turn promoted the EMT process of osteosarcoma cells by increasing the OGT.

Prognostic impact of diagnostic and treatment delays in children with osteosarcoma

BACKGROUND

The aim of this study is to evaluate the relationship between the latency to diagnosis (LD) and the time to completion of chemotherapy (TCC) with clinical outcomes in children with osteosarcoma.

METHODS

We performed a retrospective analysis of all patients who received treatment for osteosarcoma in two tertiary centers in Peru from 2008 to 2015. All causes of delayed LD or TCC were evaluated. Overall survival (OS) and event-free-survival (EFS) were estimated and compared according to LD, TCC, and established clinical prognostic factors.

RESULTS

One hundred and thirteen patients were included in the study. The median LD was 13.5 weeks (interquartile range, 10-18.5 weeks). No association was observed among clinical stage, tumor size, and LD. Delayed LD was not associated with a worse clinical outcome. Multivariate analysis confirmed that OS and EFS were significantly worse in cases of a delayed TCC (≥4 weeks), with hazard ratios of 2.70 (1.11-6.76, P = 0.003) and 1.13 (1.00-1.26, P = 0.016), respectively. Most delays in TCC (85%) were due to extramedical reasons (e.g., lack of available hospital beds).

CONCLUSION

The LD did not seem to influence the EFS and OS in pediatric patients with osteosarcoma. However, a delay in TCC from any cause is independently associated with poor outcome in pediatric patients with osteosarcoma. Based on these results, further efforts may be needed to avoid treatment delays in patients with osteosarcoma in middle-income countries.

Progress in the chemotherapeutic treatment of osteosarcoma

Osteosarcoma (OS) is the most common type of primary bone tumor in children and adolescents and has been associated with a high degree of malignancy, early metastasis, rapid progression and poor prognosis. However, the use of adjuvant chemotherapy improves the prognosis of patients with OS. OS chemotherapy is based primarily on the use of adriamycin, cisplatin (DDP), methotrexate (MTX), ifosfamide (IFO), epirubicin (EPI) and other drugs. Previous studies have revealed that the survival rate for patients with OS appears to have plateaued: 5-year survival rates remain close to 60%, even with the use of combined chemotherapy. The most limiting factors include complications and fatal toxicity associated with chemotherapy agents, particularly high-dose MTX (HD-MTX), for which high toxicity and great individual variation in responses have been observed. Docetaxel (TXT) is a representative member of the relatively recently developed taxane class of drugs, which function to inhibit OS cell proliferation and induce apoptosis. Recently, more clinical studies have reported that TXT combined with gemcitabine (GEM) is effective in the treatment of OS (relapse/refractory and progressive), providing evidence in support of potential novel treatment strategies for this patient population. However, there is still no global consensus on this type of chemotherapy approach. The present review summarizes current studies surrounding progress in the chemotherapeutic treatment of OS and discusses the advantages and potential feasibility of TXT+GEM in the treatment of OS.

ATF4 regulated by MYC has an important function in anoikis resistance in human osteosarcoma cells

Anoikis resistance is a crucial step in the process of tumor metastasis. This step determines whether the tumor cells will survive when they become detached from the extracellular matrix. However, the specific mechanism of tumor cells to bypass anoikis and become resistant remains to be elucidated. The present study aimed to determine the internal mechanism of bypassing anoikis through comparison of human osteosarcoma cell lines with human normal cell lines. High activating transcription factor 4 (ATF4) and myelocytomatosis oncogene (MYC) expression levels were observed in MG-63 and U-2 OS human osteosarcoma cell lines. It is possible that ATF4 and MYC contribute to tumor progression. Subsequently, the expression levels of ATF4 and MYC in HUVEC and CHON-001 human normal cell lines were upregulated and their adhesion abilities were reduced; whereas their ability to bypass anoikis increased significantly. Simultaneously, after we Following a knock-down of ATF4 and MYC expression levels in MG-63 and U-2 OS human osteosarcoma cell lines, their adhesion ability increased and their ability to bypassing anoikis was significantly reduced. Upregulation of MYC resulted in an upregulation of ATF4, and chromatin immunoprecipitation and luciferase reporter gene technology demonstrated that MYC binds to the promoter of ATF4. These findings suggest that ATF4 regulated by MYC might contribute to resistance to anoikis in human osteosarcoma cells.

Vitamin K4 inhibits the proliferation and induces apoptosis of U2OS osteosarcoma cells via mitochondrial dysfunction

Vitamin K (VK) is a group of fat‑soluble vitamins, which serve important roles in blood coagulation and bone metabolism. A recent study reported that several VK subtypes possess antitumor properties, however the antitumor effects of VK in osteosarcoma are unknown. The present study aimed to identify the antitumor effects of VK in osteosarcoma and the possible underlying mechanism of action. The effect of VK4 on cell viability was determined using a 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide (MTT) assay. Cellular and nuclear morphological changes were observed by phase contrast microscopy. Cell cycle analysis, apoptotic rate, mitochondrial membrane potential and levels of reactive oxygen species (ROS) were detected by flow cytometry. In vitro cancer cell migration activities were evaluated using a Wound healing assay and Transwell microplates. The results demonstrated that VK4 arrested the cells in S phase and induced apoptosis. Additional mechanistic studies indicated that the induction of apoptosis by VK4 was associated with the increased production of reactive oxygen species, dissipation of the mitochondrial membrane potential, decreased Bcl‑2 family protein expression levels and activation of caspase‑3. In conclusion, the results suggest that the sensitivity of U2OS osteosarcoma cells to VK4 may be as a result of mitochondrial dysfunction. As it is readily available for human consumption, VK4 may therefore present a novel therapeutic candidate for the treatment of patients with osteosarcoma.

Prognostic value of pathologic fracture in patients with high grade localized osteosarcoma: a systemic review and meta-analysis of cohort studies

Consensus has not been reached regarding the ability of pathologic fracture to predict local recurrence and survival in osteosarcoma. We aim to review the available evidence to examine the association between pathologic fracture and osteosarcoma prognosis. A comprehensive literature search for relevant studies published until March 2014 was performed using PubMed, Cochrane and Web of Science. The studies investigating pathologic fracture of osteosarcoma patients were systematically analyzed. The overall relative risk (RR) was estimated using a fixed-effect model or random-effect model according to heterogeneity between the trials. We included nine cohort studies involving 2,187 patients (311 with pathologic fracture and 1,876 without fracture) for the analysis of survival rate and local recurrence. Studies were assessed for quality using the Newcastle-Ottawa Assessment Scale. In the fixed-effects model, the meta-analysis showed that pathologic fracture in osteosarcoma patients predicted poor 3-year overall survival (OS) (RR=1.86, 95% CI: 1.37-2.53, p<0.001) and 5-year OS (RR=1.34, 95% CI: 1.06-1.70, p=0.016). Similarly, pathologic fracture was significantly correlated with worse 3-year event free survival (EFS) (RR=1.52, 95% CI: 1.21-1.92, p<0.001) and 5-year EFS (RR=1.24, 95% CI: 1.03-1.49, p=0.021), whereas no significant association was noted with local recurrence (RR=1.30, 95% CI: 0.84-2.02, p=0.233). The meta-analysis confirmed that pathologic fracture in osteosarcoma was a prognostic marker for both OS and EFS but not for local recurrence.