[Retracted] miR­486 suppresses the development of osteosarcoma by regulating PKC­Î´ pathway.

Following the publication of the above article, a concerned reader drew to the Editor's attention that, for the Transwell invasion and migration assay experiments shown in Figs. 5 and 6, there were multiple instances of apparently overlapping data panels, such that the data would have been derived from the same original sources where they were intended to show the results from differently performed experiments; moreover, certain of the data shown in Fig. 5B were strikingly similar to data that had appeared in Fig. 2 in a previously published paper written by different authors at different research institutes [Tian F, Ding D and Li D: Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells. Int J Oncol 46: 2355­2363, 2015]. In view of the fact that certain of the data in the above article had already appeared in a previously published paper, and given the large number of apparently overlapping data panels identified in the two referenced figures, the Editor of International Journal of Oncology has decided that this paper should be retracted from the publication. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Oncology 50: 1590­1600, 2017; DOI: 10.3892/ijo.2017.3928].

MicroRNA-519d-3p antagonizes osteosarcoma resistance against cisplatin by targeting PD-L1.

Accumulating evidence indicates that a ligand of programmed cell death receptor-1 (PD-L1) participates in the progression and recurrence of multiple malignancies, including osteosarcoma. Nevertheless, the role of PD-L1 in chemoresistance development is not fully understood. In the current study, we aim to clarify the interaction of miR-519d-3p and PD-L1 in the development of cisplatin resistance. Immunohistochemistry, quantitative reverse-transcription polymerase reaction, and Western blot were used to evaluate PD-L1 expression. MTT and transwell migration assays were used to measure cell growth and motility, respectively. ENCORI, miRCode, and miRDB databases were recruited to predict candidate miRNAs targeting PD-L1. The binding sequences of miR-519d-3p and PD-L1 3' untranslated region were identified by dual-luciferase reporter and RNA immunoprecipitation assays. Flow cytometric analysis was conducted to measure the cycle distribution and cell apoptosis. Metastatic mouse models were generated with cisplatin-resistant sublines by intravenous injection. We found that PD-L1 expression was positively correlated to cisplatin resistance and metastasis, whereas miR-519d-3p expression was reduced in cisplatin-resistant specimens and was negatively correlated to cisplatin resistance and metastasis of osteosarcoma. We demonstrated that miR-519d-3p overexpression reversed cisplatin resistance, induced G1/S phase arrest and apoptosis. In addition, we proved that miR-519d-3p inhibited lung metastasis by establishing cisplatin-resistant MG63 metastatic xenograft models. The present findings suggest that miR-519d-3p/PD-L1 axis is a novel signaling pathway contributing to cisplatin resistance. Our study provides new clues for curing refractory osteosarcoma beyond immune checkpoint inhibitors.

Keratin 9 L164P mutation in a Chinese pedigree with epidermolytic palmoplantar keratoderma, cytokeratin analysis, and literature review.

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is characterized by hyperkeratotic lesions on palms and soles. The disorder is caused by mutations of keratin 9 (KRT9) or KRT1 gene. METHODS: Epidermolytic palmoplantar keratoderma was diagnosed by physical examination and histopathological analysis in a five-generation Chinese family. Mutation was screened by Sanger sequencing. The palmar expression of multiple cytokeratins were analyzed by tape-stripping and Real-time PCR. Literatures of EPPK with additional symptoms were reviewed. RESULTS: Affected family members showed diffuse palmoplantar keratosis, with knuckle pads, friction-related lesions and a novel additional symptom of palmar constriction. A heterozygous mutation of c.T491C (p.L164P) of KRT9 was found within the helix initiation motif. The hydrophobic effect was decreased and the initiation of coiled-coil conformation was delayed. The KRT16/KRT6 expression were significantly increased in the patients, especially on the right, indicating activation of stress-response and wound-healing cytokeratins. There were also increased KRT9/KRT2, unchanged KRT10/KRT1, and undetectable KRT14/KRT5 expression. The genetic and phenotypic heterogeneity of EPPK with additional symptoms were summarized by literature review. CONCLUSION: The p.L164P mutation of KRT9 caused EPPK with a novel symptom of palmar constriction. The expression of multiple cytokeratins was altered in EPPK patients.

miR-627-3p inhibits osteosarcoma cell proliferation and metastasis by targeting PTN.

Dysregulation of microRNA (miRNA) has been observed in several types of tumors, including osteosarcoma. Biochip analysis was used to identify miRNAs differentially expressed in osteosarcoma tissues. The targeting sites of miR-627-3p were analyzed using miRDB software and fluorescein reporter gene. MTT and Transwell assays were used to analyze the effects of miR-627-3p on the growth and migration of osteosarcoma cells. Western blotting and real-time PCR were used to detect the effects of miR-627-3p on related proteins. In vivo experiments were conducted to verify the effect of miR-627-3p on osteosarcoma. We focused on miR-627-3p because it was the most significantly downregulated miRNA in our screening study. Through luciferase reporter assays, western blotting and real-time PCR we found that miR-627-3p directly targets PTN, and that expression levels of miR-627-3p and PTN are negatively correlated in osteosarcoma cells. Downregulation of miR-627-3p promoted osteosarcoma cell proliferation and metastasis, while its overexpression had the opposite effect. By targeting PTN, miR-627-3p also suppressed expression of Cyclin D1 and MMP2. MiR-627-3p inhibited osteosarcoma metastasis in vivo. Thus, miR-627-3p may be a useful therapeutic target for the treatment osteosarcoma or prevention of metastasis.

miR-141-3p is a key negative regulator of the EGFR pathway in osteosarcoma.

BACKGROUND: Many studies have used miRNA to modulate osteosarcoma development by regulating protein expression, and these studies showed that the expression of EGFR is increased in osteosarcoma. METHODS: Western blot, real-time PCR and immunohistochemical were used to detect the expression of EGFR and miR-141 in osteosarcoma tissues and cells. The correlation between miR-141 and the grading of osteosarcoma and the correlation with the survival time of the patients were analyzed. After predicting the target effect of miR-141 on EGFR by miRDB, correlation analysis was used to analyze the correlation between miR-141 and EGFR. Luciferase reporter gene, western blot and real-time PCR were used to detect the targeting effect of miR-141 on EGFR. Then we detected the effect of miR-141 on proliferation by MTT and PI staining. The effect of miR-141 on cell apoptosis was detected by Hochest33258 and AV-PI staining, and the effect of miR-141 on cell migration was detected by Transwell. The regulatory effects of miR-141 on related proteins were detected by western blot and real-time PCR. Finally, we transfected EGFR and EGFR DEL (mutation with miR-141 binding site) in osteosarcoma cells, and detected the effects of miR-141 on cell proliferation, apoptosis, migration and related proteins. RESULTS: The expression of miR-141-3p was negatively correlated with the expression of EGFR in osteosarcoma. The overexpression of miR-141-3p was not only closely related to the classification and size of the osteosarcoma but also had a negative effect on the growth and migration of the osteosarcoma through negative regulation of the expression of EGFR. MiR-141 can inhibit the growth and metastasis of osteosarcoma cells by targeting EGFR and affecting its downstream pathway proteins. CONCLUSION: Our study provides miR-141-3p may be a new theoretical basis for the treatment of osteosarcoma.

miR-486 suppresses the development of osteosarcoma by regulating PKC-δ pathway.

Osteosarcoma is one of the most highly malignant types of cancer in adolescents and young adults with a high mortality rate. Despite advances in surgery, radiation therapy and chemotherapy, the prognosis for patients with osteosarcoma has not significantly improved over the past several decades. It is necessary to find new indicators of prognosis and therapeutic targets of osteosarcoma. Through the analysis of 40 osteosarcoma tissues, we found that the expression of miR­486 was low and the expression of PKC­Î´ was high in osteosarcoma. Median survival of patients with low expression of miR-486 (30 months) was shorter than the patients with higher expression of miR­486 (40 months). We further found that miR-486 can inhibit the targeting of PKC­Î´ signaling pathways, and this inhibition can inhibit the growth and invasion of osteosarcoma cells. After transfection of miR­486 for 24 h, the proliferation of osteosarcoma cells was inhibited by ~20%, and the migration was inhibited by ~15%. In the present investigation, we demonstrated that miR­486 is negatively associated with the expression of PKC-δ and could regulate the development of osteosarcoma. miR-486 may be a potential target for the treatment of osteosarcoma.

Effect of glucocorticoids on osteoclast function in a mouse model of bone necrosis.

Osteonecrosis, also termed aseptic necrosis, is the cellular death of bone components due to interruption of the blood supply. Glucocorticoid (GC) therapy is a common non-traumatic cause of osteonecrosis. However, the mechanism by which GCs induce osteonecrosis remains to be elucidated. The aim of the present study was to investigate the effects of GCs on osteoclast and osteoblast differentiation and function in a GC­induced osteonecrosis mouse model. BALB/c male mice (n=40; 4­weeks­old) were treated with dexamethasone and asparaginase for 8 weeks. The control group (n=20) was administered normal saline. The results demonstrated that the GC-treated group had a lower mean weight compared with the control group. Morphologically, 16/37 (43%) mice demonstrated significant osteonecrotic lesions in the GC­treated group. However, osteonecrotic lesions were not observed in the mice of the control group. Furthermore, immunohistochemistry demonstrated that the GC­treated group had a higher level of osteoprotegerin compared with the control group, without any change in the expression of receptor activator of nuclear factor­κB ligand. In addition, tartarate­resistant acid-phosphatase staining demonstrated significantly decreased osteoclasts in the areas of bone destruction in the GCs-treated group. Furthermore, the present study demonstrated that GCs increased expression levels of osterix and osteocalcin, and decreased expression of matrix metallopeptidase­9 to regulate the differentiation and function of osteoblasts and osteoclasts. The results of the present study suggested that GCs influence bone remolding resulting in decreased osteoclasts formation/differentiation. Therefore, regulating the differentiation and activity of the osteoclasts may be beneficial to the control and treatment of osteonecrosis.