Osteosarcoma (OS), which occurs most commonly in adolescents, is associated with a high degree of malignancy and poor prognosis. In order to develop an accurate treatment for OS, a deeper understanding of its complex tumor microenvironment (TME) is required. In the present study, tissues were isolated from six patients with OS, and then subjected to single-cell RNA sequencing (scRNA-seq) using a 10× Genomics platform. Multiplex immunofluorescence staining was subsequently used to validate the subsets identified by scRNA-seq. ScRNA-seq of six patients with OS was performed prior to neoadjuvant chemotherapy, and data were obtained on 29,278 cells. A total of nine major cell types were identified, and the single-cell transcriptional map of OS was subsequently revealed. Identified osteoblastic OS cells were divided into five subsets, and the subsets of those osteoblastic OS cells with significant prognostic correlation were determined using a deconvolution algorithm. Thereby, different transcription patterns in the cellular subtypes of osteoblastic OS cells were reported, and key transcription factors associated with survival prognosis were identified. Furthermore, the regulation of osteolysis by osteoblastic OS cells via receptor activator of nuclear factor kappa-B ligand was revealed. Furthermore, the role of osteoblastic OS cells in regulating angiogenesis through vascular endothelial growth factor-A was revealed. C3_TXNIP+ macrophages and C5_IFIT1+ macrophages were found to regulate regulatory T cells and participate in CD8+ T cell exhaustion, illustrating the possibility of immunotherapy that could target CD8+ T cells and macrophages. Our findings here show that the role of C1_osteoblastic OS cells in OS is to promote osteolysis and angiogenesis, and this is associated with survival prognosis. In addition, T cell depletion is an important feature of OS. More importantly, the present study provided a valuable resource for the in-depth study of the heterogeneity of the OS TME.

BackgroundSeveral observational studies have suggested an association between cigarette smoking and risk of hip fracture. However, no formal systematic review or meta-analysis was performed to summarize this risk in men.Materials and MethodsA search was applied to MEDLINE, EMBASE, and web of science (up to November 1 2016). All prospective cohort studies assessing risk of hip fracture with the factor of cigarette smoking in men without language restriction were reviewed, and qualities of all included studies were assessed using the Newcastle-Ottawa Scale. Two authors independently assessed literatures and extracted information eligibility, and any disagreement was resolved by consensus. Newcastle-Ottawa quality assessment scale was used to evaluate studies’ quality in meta-analyses. We calculated the RR with 95% CIs in a random-effects model as well as the fixed-effects model using the metan command in the STATA version 12.0 (StataCorp, USA).ResultsFourteen prospective cohort studies were eligible for the present analysis. A meta-analysis of 12 prospective studies showed that the relative risk (RR) for current male smoking was 1.47 [95% confidence interval (CI) (1.28–1.66), p = 0.54; I2 = 0%]. Subgroup analyses show study characteristics (including geography region, length of follow-up, size of cohorts and study quality) did not substantially influence these positive associations. Eight studies reported the RRs for former smokers compared with never smokers and the pooled RR was 1.15 [95% CI, (0.97–1.34), (I2 = 0%, p = 0.975)].ConclusionsThe present meta-analysis of 14 prospective studies suggests that, compared with never smokers, cigarette smoking increases risk of hip fracture in man, specifically in current smokers. However, further larger prospective cohorts with more power or meta-analysis of individual patient data are needed to confirm this association.

Microendoscopic discectomy, which requires a demanding learning curve, may be a safe and effective alternative to conventional open discectomy for patients with lumbar disc herniation.

BackgroundPLK1, a typical PLK protein, is the main driver of cancer cell growth and proliferation. It is an inhibitor of the protein kinases that is currently being investigated in clinical studies. It is often used as a tumor marker, as high PLK1 expression correlates with poor prognosis in cancer. Overexpression of MYC is a hallmark of many human cancers. MYC modulates the transcription of thousands of genes that required to coordinate a series of cellular processes, including those essential for growth, proliferation, differentiation, self-renewal and apoptosis. To date, functions of PLK1 and MYC on tumor are mostly studied in separate researches, and studies on their mutual crosstalk are lacking.PurposeTo investigate the mechanism of PLK1 and MYC in regulating progress of osteosarcoma.MethodsProtein level was examined using Western blot. Animal experiments were performed with female FOX CHASE severe combined immunodeficient mice. Mice were randomly divided into experimental or control groups.ResultsPLK1 or MYC promoted the proliferation of osteosarcoma cells through the autophagy pathway. PLK1 contributed to MYC protein stabilization. PLK1 inhibition enhanced MYC degradation in osteosarcoma cells. PLK1 inhibition led to a marked decline in MYC protein abundance. The representative MYC target genes were deregulated by PLK1 inhibitors. BI2536 treatment caused a significant delay in xenograft tumor growth in mice injected with U-2 OS cells subcutaneously, with lower mean tumor weight compared to the control group.ConclusionPLK1 is crucial for MYC stabilization. It promotes cell proliferation by autophagy pathway in osteosarcoma cells. Data validate PLK1 as a potential therapeutic target in osteosarcoma caused by MYC-amplified.

PurposeBy examining and identifying circulating tumor cell (CTC) counts and subtypes of peripheral blood in osteosarcoma patients, we evaluated the relationship between CTCs and characteristics of osteosarcoma patients, as well as CTC changes after neoadjuvant chemotherapy and surgery.MethodsCanPatrol™ CTC technology was used to detect CTCs in peripheral blood before and after treatment in 32 osteosarcoma patients. Peripheral blood samples from 10 healthy volunteers were included as controls and examined for the presence of CTCs.ResultsOf the 32 osteosarcoma patients, CTCs were detected in 30 patients before treatment, and the average CTC count was 14.06±9.08. No CTCs were detected in the 10 healthy volunteers. The detected CTCs were divided into epithelial CTCs, mesenchymal CTCs (M-CTCs), and biophenotypic epithelial/mesenchymal CTCs. The average number of pretreatment CTCs was higher in stage III patients than in stage IIB patients (P=0.012). Twenty-eight patients were screened for changes in CTC count at 1 week after neoadjuvant chemotherapy and at 4 weeks after surgery. We divided these 28 patients into two groups according to the changes in the percentage of M-CTCs before and after treatment, and the results showed that the disease-free survival (DFS) was significantly shorter in the M-CTC percentage-increased group than in the M-CTC percentage-decreased or no-change group (P=0.032). Five patients with stage II osteosarcoma were examined for CTCs at the appearance of lung metastases, and the total number of CTCs was found to be higher at the appearance of lung metastases than before treatment in these patients.ConclusionThe rate of presence of CTCs in the peripheral blood of osteosarcoma patients is high, and patients with an increased percentage of M-CTCs after treatment have a shorter DFS. The dynamic monitoring of changes in CTC counts after treatment has clinical significance for the timely detection of recurrence or metastasis.