Prognostic value of bax, cytochrome C, and caspase-8 protein expression in primary osteosarcoma

New challenges in integrated diagnosis by imaging and osteo-immunology in bone lesions

INTRODUCTION

High-resolution imaging is the gold standard to measure the functional and biological features of bone lesions. Imaging markers have allowed the characterization both of tumour heterogeneity and metabolic data. Besides, ongoing studies are evaluating a combined use of 'imaging markers', such as SUVs, MATV, TLG, ADC from PET and MRI techniques respectively, and several 'biomarkers' spanning from chemokine immune-modulators, such as PD-1, RANK/RANKL, CXCR4/CXCL12 to transcription factors, such as TP53, RB1, MDM2, RUNX family, EZH2, YY1, MAD2. Osteoimmunology may improve diagnosis and prognosis leading to precision medicine in bone lesion treatment. Areas covered: We investigated modalities (molecular and imaging approach) useful to identify bone lesions deriving both from primary bone tumours and from osteotropic tumours, which have a higher incidence, prevalence and prognosis. Here, we summarized the recent advances in imaging techniques and osteoimmunology biomarkers which could play a pivotal role in personalized treatment. Expert commentary: Although imaging and molecular integration could allow both early diagnosis and stratification of cancer prognosis, large scale clinical trials will be necessary to translate pilot studies in the current clinical setting.

ABBREVIATIONS

ADC: apparent diffusion coefficient; ALCAM: Activated Leukocyte Cell Adhesion Molecule; ALP: Alkaline phosphatases; BC: Breast cancer; BSAP: B-Cell Lineage Specific Activator; BSAP: bone-specific alkaline phosphatase; BSP: bone sialoprotein; CRIP1: cysteine-rich intestinal protein 1; CD44: cluster of differentiation 44; CT: computed tomography; CXCL12: C-X-C motif ligand 12; CXCR4: C-X-C C-X-C chemokine receptor type 4; CTLA-4: Cytotoxic T-lymphocyte antigen 4; CTX-1: C-terminal end of the telopeptide of type I collagen; DC: dendritic cell; DWI: Diffusion-weighted MR image; EMT: mesenchymal transition; ET-1: endothelin-1; FDA: Food and Drug Administration; FDG: ¹⁸F-2-fluoro-2-deoxy-D-glucose; FGF: fibroblast growth factor; FOXC2: forkhead box protein C2: HK-2: hexokinase-2; ICTP: carboxyterminal cross-linked telopeptide of type I collagen; IGF-1R: Insulin Like Growth Factor 1 Receptor; ILC: innate lymphocytes cells; LC: lung cancer; IL-1: interleukin-1; LYVE1: lymphatic vessel endothelial hyaluronic acid receptor 1; MAD2: mitotic arrest deficient 2; MATV: metabolically active tumour volume; M-CSF: macrophage colony stimulating factor; MM: multiple myeloma; MIP1a: macrophage inflammatory protein 1a; MSC: mesenchymal stem cell; MRI: magnetic resonance imaging; PC: prostate cancer; NRP2: neuropilin 2; OPG: osteoprotogerin; PDGF: platelet-derived growth factor; PD-1: Programmed Cell Death 1; PET: positron emission tomography; PINP: procollagen type I N propeptide; PROX1: prospero homeobox protein 1; PSA: Prostate-specific antigen; PTH: parathyroid hormone; RANK: Receptor activator of NF-kB ligand; RECK: Reversion-inducing-cysteine-rich protein; SEMAs: semaphorins; SPECT: single photon computed tomography; SUV: standard uptake value; TLG: total lesion glycolysis; TP53: tumour protein 53; VCAM-1: vascular endothelial molecule-1; VOI: volume of interest; YY1: Yin Yang 1.

Biomarkers of Osteosarcoma, Chondrosarcoma, and Ewing Sarcoma

Osteosarcoma is the most frequent malignant bone neoplasm, followed by chondrosarcoma and Ewing sarcoma. The diagnosis of bone neoplasms is generally made through histological evaluation of a biopsy. Clinical and radiological features are also important in aiding diagnosis and to complete the staging of bone cancer. In addition to these, there are several non-specific serological or specific molecular markers for bone neoplasms. In bone tumors, molecular markers increase the accuracy of the diagnosis and assist in subtyping bone tumors. Here, we review these markers and discuss their role in the diagnosis and prognosis of the three most frequent malignant bone neoplasms, namely osteosarcoma, chondrosarcoma, and Ewing sarcoma.

Triptolide induces the cell apoptosis of osteosarcoma cells through the TRAIL pathway

Research on triptolide, a diterpenoid epoxide found in the Thunder God Vine Tripterygium wilfordii, has increased our knowledge of the pharmacology, pharmacokinetics, toxicology and clinical application of this agent. In the present study, we aimed to identify the effects of triptolide on the apoptosis of osteosarcoma cells and to evaluate the anti-proliferative action of this agent. MG-63 cells were treated either with various doses of triptolide (50, 100 or 200 nM) or DMSO for 6, 12 and 24 h. Treatment with triptolide effectively suppressed the cell viability and induced the apoptosis of osteosarcoma MG-63 cells as detected by MTT assay and flow cytometry, respectively. In addition, by using caspase-3, caspase-8 and caspase-9 activity assays and western blot analysis, the anticancer effects of triptolide against osteosarcoma growth were found to involve activation of the DR-5/p53/Bax/caspase-9/ caspase-3 signaling pathway and the DR-5/FADD/caspase-8/lysosomal/cathepsin B/caspase-3 signaling pathway in the MG-63 cells. An important factor in the anticancer effects of triptolide against osteosarcoma was TRAIL-DR-5. The data suggest that triptolide may be a potential novel chemotherapeutic agent for osteosarcoma and acts through the TRAIL-DR-5 signaling pathway.

Proliferation index: a continuous model to predict prognosis in patients with tumours of the Ewing's sarcoma family

The prognostic value of proliferation index (PI) and apoptotic index (AI), caspase-8, -9 and -10 expression have been investigated in primary Ewing's sarcoma family of tumours (ESFT). Proliferating cells, detected by immunohistochemistry for Ki-67, were identified in 91% (91/100) of tumours with a median PI of 14 (range 0-87). Apoptotic cells, identified using the TUNEL assay, were detected in 96% (76/79) of ESFT; the median AI was 3 (range 0-33). Caspase-8 protein expression was negative (0) in 14% (11/79), low (1) in 33% (26/79), medium (2) in 38% (30/79) and high (3) in 15% (12/79) of tumours, caspase-9 expression was low (1) in 66% (39/59) and high (3) in 34% (20/59), and caspase-10 protein was low (1) in 37% (23/62) and negative (0) in 63% (39/62) of primary ESFT. There was no apparent relationship between caspase-8, -9 and -10 expression, PI and AI. PI was predictive of relapse-free survival (RFS; p = 0.011) and overall survival (OS; p = <0.001) in a continuous model, whereas AI did not predict outcome. Patients with tumours expressing low levels of caspase-9 protein had a trend towards a worse RFS than patients with tumours expressing higher levels of caspase-9 protein (p = 0.054, log rank test), although expression of caspases-8, -9 and/or -10 did not significantly predict RFS or OS. In a multivariate analysis model that included tumour site, tumour volume, the presence of metastatic disease at diagnosis, PI and AI, PI independently predicts OS (p = 0.003). Consistent with previous publications, patients with pelvic tumours had a significantly worse OS than patients with tumours at other sites (p = 0.028); patients with a pelvic tumour and a PI≥20 had a 6 fold-increased risk of death. These studies advocate the evaluation of PI in a risk model of outcome for patients with ESFT.

Molecular mechanisms of chemoresistance in osteosarcoma (Review)

Due to the emergence of adjuvant and neoadjuvant chemotherapy, the survival rate has been greatly improved in osteosarcoma (OS) patients with localized disease. However, this survival rate has remained unchanged over the past 30 years, and the long-term survival rate for OS patients with metastatic or recurrent disease remains poor. To a certain extent, the reason behind this may be ascribed to the chemoresistance to anti-OS therapy. Chemoresistance in OS appears to be mediated by numerous mechanisms, which include decreased intracellular drug accumulation, drug inactivation, enhanced DNA repair, perturbations in signal transduction pathways, apoptosis- and autophagy-related chemoresistance, microRNA (miRNA) dysregulation and cancer stem cell (CSC)-mediated drug resistance. In addition, methods employed to circumvent these resistance mechanism have been shown to be effective in the treatment of OS. However, almost all the current studies on the mechanisms of chemoresistance in OS are in their infancy. Further studies are required to focus on the following aspects: i) Improving the delivery of efficacy through novel delivery patterns; ii) improving the understanding of the signal transduction pathways that regulate the proliferation and growth of OS cells; iii) elucidating the signaling pathways of autophagy and its association with apoptosis in OS cells; iv) utilizing high-throughput miRNA expression analysis to identify miRNAs associated with chemoresistance in OS; and v) identifying the role that CSCs play in tumor metastasis and in-depth study of the mechanism of chemoresistance in the CSCs of OS.

Prognostic markers in osteosarcoma

Osteosarcoma is the most common bone tumor seen in the pediatric and adolescent age group. Survival rates in osteosarcoma have improved considerably from 20 to 65% since the 1980s with the advent of multiagent chemotherapy. Further improvement in survival has not been achieved owing to lack of well-validated prognostic markers and better therapeutic agents. Markers involved with angiogenesis, cell adhesion, apoptosis and cell cycle have been shown recently to play an important role in osteosarcoma growth, differentiation and metastasis. Over the coming years, the new molecular markers may be able not only to prognosticate osteosarcoma patients at baseline but also to serve as therapeutic targets and thereby improve survival rates further. Noninvasive imaging methods in osteosarcoma such as PET-CT and dynamic contrast enhanced and diffusion-weighted MRI hold a lot of promise as surrogate methods for prognostication and response assessment.