Complications of Paget Bone Disease: A Study of 69 Patients

INTRODUCTION

Paget bone disease (PBD) is characterized by a disorder in the bone remodeling activity at sites of involvement. This can produce dramatic alterations of local bone architecture and causes most of the complications. We aimed to focus on the characteristics of complications of PDB among hospitalized patients.

MATERIAL AND METHODS

A retrospective study was conducted, on PBD patients hospitalized in two rheumatology centers from 1994 to 2019. Characteristics of the PBD complications were studied.

RESULTS

Sixty-nine patients were collected with a sex ratio of 0.76 and a mean age of 75.4±6.4 years [43-101]. The diagnosis of PBD was established in the average age of 64.2±11.5 years. The primary reason for consultation was pain (78.3%). The PBD was localized in the pelvis (58%), lower limb (42%), spine (36.2%), skull (23.2%) and upper limb (5.8%). It was polyostotic in 44.9% of cases. Dosage of ALP was 324 [68-8390]. The PDB complication rate was 52.2% and it decreased over time. The main complication was osteoarthritis (23.2%), followed by deafness (17.4%), fracture (15.9%), hydrocephalus (7.2%), neurological disease (7.2%) and osteosarcoma (1.4%). The presence of complications was significantly associated with the polyostotic form (p=0.01), the skull localization (p=0.04), an increased ALP (p=0.02).

CONCLUSION

According to our study, the incidence rate of PBD among hospitalized cases is higher among elderly women and decreases over time. Complications related to PDB are frequent (52%). It concerns patients with a polyostotic form, skull localization and high ALP.

The Function of LncRNA FTX in Several Common Cancers

BACKGROUND

LncRNA is a kind of non-coding RNA and its research is more popular in recent years, which has more than 200 nucleotides. It plays a significant part in various biological functions, including chromosome modification, genome modification, transcriptional activation, transcriptional interference, and other processes. FTX, at the center of the X chromosome inactivation and it has been shown that lncRNA FTX regulates cancer cells' development, migration, and invasion in many studies.

METHODS

Relevant literature was collected through the PubMed system search and is summarized in this article.

RESULTS

LncRNA FTX abnormally increased in tumor cells, such as liver cancer, stomach cancer, leukemia, renal cell carcinoma, colorectal cancer, glioma, osteosarcoma, etc. However, the expression level decreased in temporal lobe epilepsy, liver cirrhosis, heart failure, etc. Conclusion: FTX may be an important regulatory factor and a potential therapeutic target in cancers.

Profiling of Autophagy-Associated microRNAs in the Osteosarcoma Cell Line of U2OS

BACKGROUND

Autophagy is a cellular process that plays a role in the destruction of proteins and organelles. It has been shown that impaired autophagic flux triggers canceration, infectious disease, and neurodegenerative diseases. It has been suggested that tumor formation is inhibited by autophagy that reduces oxidative stress and recycles damaged organelles. microRNAs are 17-25 bp in length, single-stranded, and noncoding small RNAs that play roles in the regulation of metabolic gene expression at the post-transcriptional level. Osteosarcoma is an aggressive bone cancer that affects mainly children and adolescents.

OBJECTIVE

The current article aims to profile autophagy-associated miRNAs in osteosarcoma cell lines and to examine the therapeutical potentials of these miRNAs by suppressing their expressions with Adriamycin and Rapamycin.

METHODS

We used fluidigm dynamic array nanofluidic chip 96.96 for mRNA expression assay in osteosarcoma cell line U2OS.

RESULTS

It was probed that after the suppression of autophagy-associated miRNAs by adriamycin and rapamycin, while most of the miRNAs were down-regulated in osteosarcoma cell lines, some miRNAs' expressions, such as miR-3141, miR-4296, miR-133b, and miR-720, were strikingly increased. Rapamycin and adriamycin, mTOR inhibitors, stir autophagic machinery, which results in decreased cell survival.

CONCLUSION

Together, we propose that the expressions of miR-3141, miR-4296, miR-133b, and miR-720 might exacerbate the pathogenesis of osteosarcoma; therefore, the suppression of these miRNAs with the loss-offunction approaches could be an appropriate strategy that is worth testing in osteosarcoma.

LncRNA, Important Player in Bone Development and Disease

BACKGROUND

Bone is an important tissue and its normal function requires tight coordination of transcriptional networks and signaling pathways, and many of these networks/ pathways are dysregulated in pathological conditions affecting cartilage and bones. Long non-coding RNA (lncRNA) refers to a class of RNAs with a length of more than 200 nucleotides, lack of protein-coding potential, and exhibiting a wide range of biological functions. Although studies on lcnRNAs are still in their infancy, they have emerged as critical players in bone biology and bone diseases. The functions and exact mechanism of bone-related lncRNAs have not been fully classified yet.

OBJECTIVE

The objective of this article is to summarize the current literature on lncRNAs on the basis of their role in bone biology and diseases, focusing on their emerging molecular mechanism, pathological implications and therapeutic potential.

DISCUSSION

A number of lncRNAs have been identified and shown to play important roles in multiple bone cells and bone disease. The function and mechanism of bone-related lncRNA remain to be elucidated.

CONCLUSION

At present, majority of knowledge is limited to cellular levels and less is known on how lncRNAs could potentially control the development and homeostasis of bone. In the present review, we highlight some lncRNAs in the field of bone biology and bone disease. We also delineate some lncRNAs that might have deep impacts on understanding bone diseases and providing new therapeutic strategies to treat these diseases.

circEPSTI1 Acts as a ceRNA to Regulate the Progression of Osteosarcoma

BACKGROUND

Recent studies have reported the vital roles of circular RNAs (circRNAs) in tumor progression. However, the function and expression profile of most circRNAs in osteosarcoma remain unclear.

METHODS

We examined the expression of circEPSTI1, a circRNA, in 50 paired adjacent normal tissues and osteosarcoma tissues by qRT-PCR. Then, we further explored the function of circEPSTI1 in osteosarcoma progression in vitro and in vivo. For example, cell proliferation and migration were examined. Some experiments were performed to explore the regulatory function of circEPSTI1 in miRNA and to investigate the potential role of circEPSTI1 in osteosarcoma.

RESULTS

We found that circEPSTI1 was significantly upregulated in osteosarcoma. Inhibition of circEPSTI1 suppressed the osteosarcoma cancer cell proliferation and migration in vitro. Dual luciferase reporter assay showed that circEPSTI1 and MCL1 (myeloid cell leukaemia 1) could bind to miR-892b and that MCL1 and circEPSTI1 were targets of miR-892b.

CONCLUSION

Thus, the circEPSTI1-miR-892b-MCL1 axis affected osteosarcoma progression through the miRNA sponging mechanism. circEPSTI1 may serve as a target and biomarker for osteosarcoma treatment.

Down-regulation of RPS9 Inhibits Osteosarcoma Cell Growth through Inactivation of MAPK Signaling Pathway

Objectives: Osteosarcoma is the most common malignant bone tumor in adolescents; however, the mechanisms involved in the pathogenesis and progression of osteosarcoma remain to be elucidated. Researchers have provided valuable insights into the tumorigenesis of Ribosomal protein S9 (RPS9) in some cancers. The purpose of this study was to elucidate the expression, functions, and mechanisms of RPS9 in human osteosarcoma. Methods: The expression of RPS9 in osteosarcoma tissues and cell lines was evaluated by qRT-PCR and western blotting. Knockdown of RPS9 induced by RNA interference (RNAi) method in three osteosarcoma cell lines (MNNG/HOS, MG63, and U2OS) was employed to analyze the effects of RPS9 on cell proliferation and cell cycle distribution. The host signaling pathways affected by RPS9 were detected using the intracellular signaling antibody array kit PathScan^®. Results: The expression of RPS9 was found to be up-regulated in human osteosarcoma tissues and cell lines. Its expression was positively correlated with Enneking stage and the tumor recurrence. Down-regulation of RPS9 inhibited osteosarcoma cell proliferation, colony-forming ability, and cell cycle G1 phase in vitro. In addition, our data demonstrated that knockdown of RPS9 repressed the protein levels of phospho-SAPK/JNK and phospho-p38. Conclusion: RPS9 is up-regulated and has a pro-tumor effect in osteosarcoma through the activation of MAPK signaling pathway and thus can be used as a potential target for gene therapy.

DNA Methylation Mediated Downregulation of miR-449c Controls Osteosarcoma Cell Cycle Progression by Directly Targeting Oncogene c-Myc

MicroRNAs (miRNAs) are critical regulators of gene expression, and they have broad roles in the pathogenesis of different diseases including cancer. Limited studies and expression profiles of miRNAs are available in human osteosarcoma cells. By applying a miRNA microarray analysis, we observed a number of miRNAs with abnormal expression in cancerous tissues from osteosarcoma patients. Of particular interest in this study was miR-449c, which was significantly downregulated in osteosarcoma cells and patients, and its expression was negatively correlated with tumor size and tumor MSTS stages. Ectopic expression of miR-449c significantly inhibited osteosarcoma cell proliferation and colony formation ability, and caused cell cycle arrest at the G1 phase. Further analysis identified that miR-449c was able to directly target the oncogene c-Myc and negatively regulated its expression. Overexpression of c-Myc partially reversed miR-449c-mimic-inhibited cell proliferation and colony formation. Moreover, DNA hypermethylation was observed in two CpG islands adjacent to the genomic locus of miR-449c in osteosarcoma cells. Conversely, treatment with the DNA methylation inhibitor AZA caused induction of miR-449c. In conclusion, our results support a model that DNA methylation mediates downregulation of miR-449c, diminishing miR-449c mediated inhibition of c-Myc and thus leading to the activation of downstream targets, eventually contributing to osteosarcoma tumorigenesis.

Suppression of PinX1 resulted in telomere dysfunction and enhanced radiosensitivity in osteosarcoma cell lines

Telomeres have emerged as a promising and important factor modulating cellular and organism responses to ionizing radiation (IR). Pin2/TRF1 interacting protein X1 (PinX1) is an intrinsic telomerase inhibitor and a putative tumor suppressor gene in human cancers. The aim of this study is to investigate the role PinX1 in osteosarcoma (OS) radioresistance. A telomerase-positive OS cell line Saos-2 and a telomerase-negative OS cell line U2OS were used. PinX1 shRNA lentiviral vetors were constructed and transfected to cells. PinX1 expression was determined by real-time quantitative PCR (qPCR) and Western blotting. Relative telomere length (RTL) was detected by using qPCR. Flow cytometric analysis was used to detect cell cycle and apoptosis. Radiosensitivity was determined by colony formation assay. Data showed that, PinX1 knockdown resulted in telomere shortening, G1 phase arrest, increased apoptosis and enhanced IR sensitivity both in Saos-2 and U2OS cell lines, regardless of telomerase status. Our study concluded that PinX1 could serve as a novel predictor for radiotherapy response to OS patients, and the pathway of PinX1-mediated telomere stability might represent a new target to improve the radiotherapy effect of OS.

The epidemiology of malignant giant cell tumors of bone: an analysis of data from the Surveillance, Epidemiology and End Results Program (1975-2004)

Malignant giant cell tumor (GCT) of bone is a rare tumor with debilitating consequences. Patients with GCT of bone typically present with mechanical difficulty and pain as a result of bone destruction and are at an increased risk for fracture. Because of its unusual occurrence, little is known about the epidemiology of malignant GCT of bone. This report offers the first reliable population-based estimates of incidence, patient demographics, treatment course and survival for malignancy in GCT of bone in the United States. Using data from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program, we estimated the overall incidence and determinants of survival among patients diagnosed with malignant GCT of bone from 1975–2004. Cox proportional hazards regression was used to evaluate demographic and clinical determinants of survival among malignant GCT cases. Based on analyses of 117 malignant GCT cases, the estimated annual incidence in the United States was 1.6 per 10,000,000 persons per year. Incidence was highest among adults aged 20 to 44 years (2.4 per 10,000,000 per year) and most patients were diagnosed with localized (31.6%) or regional (29.9%) disease compared to distant disease (16.2%). Approximately 85% of patients survived at least 5 years, with survival poorest among older patients and those with evidence of distant metastases at time of diagnosis. The current study represents the largest systematic investigation examining the occurrence and distribution of malignancy in GCT of bone in the general U.S. population. We confirm its rare occurrence and suggest that age and stage at diagnosis are strongly associated with long-term survival.