Multiple relapses in high-grade osteosarcoma: when to stop aggressive therapy?

MiR-139 inhibits proliferation, migration and invasion of osteosarcoma cell line MG63 via down-regulating integrin subunit alpha V(ITGAV)

OBJECTIVES

Osteosarcoma is a relatively common primary malignant bone tumor in clinic, which frequently occurs in children and adolescents. It is essential to clarify the molecular mechanism of osteosarcoma to provide better diagnosis and treatment. Abnormal expression of miRNAs is closely related to the pathogenesis and progression of osteosarcoma. MiRNAs play a regulatory role in tumorigenesis and development of osteosarcoma. The purpose of this study is to reveal the working mechanism of miR-139/ITGAV axis in osteosarcoma progression.

METHODS

ITGAV and miR-139 expression was detected in osteosarcoma tissues or paracancerous normal tissues. TargetScan and Double luciferase reporter gene assay were adopted to verify weather ITGAV was the target gene of miR-139. Western blot and qRT-PCR were used to evaluate the effects of miR-139 on ITGAV. CCK8, Flow cytometry, Transwell and Cell wound scratch assay were used to measure the effects of miR-139 and ITGAV on cell cycle, proliferation, migration and invasion of MG63, respectively. A nude mouse xenograft model of cervical cancer was constructed to observe the effects of miR-139 on the tumor growth.

RESULTS

We found that the expression of miR-139 in osteosarcoma tissue was significantly reduced, while the expression of ITGAV was significantly increased. MiR-139 could specifically bind to the 3'-UTR of ITGAV and negatively regulate its expression. Transfection of miR-139 mimic could inhibit the proliferation, S-phase arrest, invasion and migration of MG63 cells, and up-regulating the expression of ITGAV could reverse such inhibitory effect. In nude mouse xenograft model of osteosarcoma, overexpression of miR-139 could inhibit tumor growth, while down-regulation of miR-139 produced the opposite effect.

CONCLUSIONS

These results indicate that miR-139/ITGAV axis was related to osteosarcoma initiation. MiR-139 could inhibit the biological behavior of osteosarcoma cells and the tumor growth in nude mouse model via targeting ITGAV, and miR-139/ITGAV axis may impede the progression of osteosarcoma.

A multicentric randomized phase II clinical trial evaluating high-dose thiotepa as adjuvant treatment to standard chemotherapy in patients with resectable relapsed osteosarcoma

BACKGROUND

The role of high-dose chemotherapy in relapsing osteosarcomas has not been established. We evaluated the efficacy and tolerance of high-dose thiotepa (HDTp) after standard chemotherapy (SCT) in patients with relapsed osteosarcoma.

PATIENTS AND METHODS

This randomised open-label phase II study enrolled patients 1-50 years, with local or metastatic relapse of a high-grade osteosarcoma, not progressive after two cycles of SCT, for whom a complete surgery can be achievable following treatment. The trial assigned enrolled patients in a 1:1 ratio to receive two additional courses of SCT + HDTp and autologous transplantation (Arm A), or SCT alone (Arm B). Surgery for complete resection was scheduled as soon as feasible. Primary endpoint was overall survival (OS). Secondary objectives included progression-free survival (PFS) and safety.

RESULTS

From September 2009 to November 2016, 44 patients were randomised (A:22; B:22). In total, 54.5% were males, and the median age was 16 years (9-32years). The two-year OS rate was 66.7% (95% CI 42.5-82.5) (SCT + HDTp, Arm A) versus 50.0% (95% CI 28.2-68.4) for SCT alone (Arm B). Median OS was 27.4 and 24.8 months, respectively (hazard ratio [HR] 0.826, 95% CI 0.393-1.734; p = 0.6123). Median PFS was 15.6 (8.9-24.9) months in Arm A versus 7.2 (4.8-33.3) months in Arm B, p = 0.3845. Among the 22 patients treated with SCT + HDTp, 16 (72.7%) experienced at least one grade ≥3 adverse events versus 18/22 (81.8%) patients treated with SCT. No toxic death occurred.

CONCLUSION

Adjuvant HDTp failed to significantly improve OS and PFS in resectable relapsed osteosarcomas. Despite a trend of prolonged survival and an acceptable toxicity, thiotepa cannot be recommended.

KEY MESSAGE

HDTp and autologous transplantation added to SCT did not improve OS and PFS in patients with resectable relapsed osteosarcomas. Despite a trend of prolonged survival, thiotepa cannot be recommended.

An update on emerging drugs in osteosarcoma: towards tailored therapies?

Introduction: Current treatment of conventional and non-conventional high-grade osteosarcoma (HGOS) is based on the surgical removal of primary tumor and, when possible, of metastases and local reccurrence, together with systemic pre- and post-operative chemotherapy with drugs that have been used since decades. Areas covered: This review is intended to summarize the new agents and therapeutic strategies that are under clinical evaluation in HGOS, with the aim to increase the cure probability of this highly malignant bone tumor, which has not significantly improved during the last 30-40 years. The list of drugs, compounds and treatment modalities presented and discussed here has been generated by considering only those that are included in presently ongoing and recruiting clinical trials, or which have been completed in the last 2 years with reported results, on the basis of the information obtained from different and continuously updated databases. Expert opinion: Despite HGOS is a rare tumor, several clinical trials are presently evaluating different treatment strategies, which may hopefully positively impact on the outcome of patients who experience unfavorable prognosis when treated with conventional therapies.

Cytotoxic Tolerance of Healthy and Cancerous Bone Cells to Anti-microbial Phenolic Compounds Depend on Culture Conditions

Carnosol and carnosic acid are polyphenolic compounds found in rosemary and sage with known anti-oxidant, anti-inflammatory, and anti-microbial properties. Here, we addressed the potential use of carnosol and carnosic acid for in vitro bone tissue engineering applications, specifically depending on their cytotoxic effects on bone marrow stromal and stem cells, and osteosarcoma cells in monolayer and 3D cultures. Carnosol and carnosic acid displayed a bacteriostatic effect on Gram-positive bacteria, especially on S. aureus. The viability results indicated that bone marrow stromal cells and bone marrow stem cells were more tolerant to the presence of carnosol compared to osteosarcoma cells. 3D culture conditions increased this tolerance further for healthy cells, while not affecting the cytotoxic potential of carnosol for osteosarcoma cells. Carnosic acid was found to be more cytotoxic for all cell types used in the study. Results suggest that phenolic compounds might have potential use as anti-microbial and anti-carcinogenic agents for bone tissue engineering with further optimization for controlled release.