Retraction Note: Glycol chitosan incorporated retinoic acid chlorochalcone (RACC) nanoparticles in the treatment of Osteosarcoma.

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1186/s12944-020-01416-2.

[Research on the knockout of LMNA gene by CRISPR/Cas9 system in human cell lines].

The LMNA gene encodes the nuclear Lamin A and Lamin C proteins, and is related to nuclear membrane organization, genome stability and cell differentiation. Abnormal expression of LMNA is ubiquitous in human tumors, and its mutation leads to various forms of laminopathies, including Emery-Dreifuss muscular dystrophy (EDMD), dilated cardiomyopathy (DCM), and Hutchinson-Gliford progeria syndrome (HGPS). To further determine the functions of the LMNA gene in cellular physiology, the present study used the CRISPR/Cas9 technique to edit the LMNA gene of 293T and HepG2 cells in vitro, which resulted in two stable LMNA gene knockout (LMNA KO) cell lines. Compared to the respective wild type cells, the LMNA KO cell lines showed decrease in proliferation ability, increase in apoptosis, alteration in cellular morphology and uneven structures in the nucleus membrane. In this study, we report for the first time the results on the construction of LMNA KO immortalized cell lines and characterization of their morphological changes, thereby laying the foundation for the further studies of the LMNA gene functions and pathogenic mutations.

Glycol chitosan incorporated retinoic acid chlorochalcone (RACC) nanoparticles in the treatment of Osteosarcoma.

BACKGROUND: Osteosarcoma is the most common of all the bone malignancies and accounts for 30-80% of the primary skeletal sarcomas. The overall survival rate of patients with osteosarcoma is < 20% suggesting poor prognosis. METHODS: The present study demonstrates the effect of retinoic acid chlorochalcone (RACC) incorporated glycol chitosan (GC) nanoparticle transfection in osteosarcoma cells. MG-63 and Saos-2 osteosarcoma cells were transfected with various concentrations of RACC-incorporated GC nanoparticle for 24 h. The effect on cell proliferation, Ezh2 expression, apoptosis, cell cycle arrest, cell migration and invasiveness, Akt phosphorylation and local tumour growth and metastases were studied. RESULTS: MG-63 and Saos-2 osteosarcoma cells on RACC-incorporated GC nanoparticle transfection for 24 h showed a concentration-dependent inhibition of cell proliferation. Of the various concentrations of RACC tested, the effective concentration started from 5 µM with an IC50 of 20 µM. Wound healing assay also showed that RACC-incorporated GC nanoparticles inhibited migration of tumor cells more effectively compared to the parent RA. RACC transfection resulted in inhibition of cell proliferation, Ezh2 expression inhibition, apoptosis through mitochondrial pathway by decrease in membrane potential and release of cytochrome c and cell cycle arrest in the G0/G1 phase. The invasiveness of cells treated with 5 and 20 µM RACC was decreased by 49 and 76% respectively, compared to the control. RACC-treated mice showed significantly lower number of metastases compared to that in the control mice. CONCLUSIONS: Thus, RACC-incorporated glycol chitosan nanoparticle strategy can be promising for the treatment of osteosarcoma.

Three-dimensional reconstruction method for measuring the knee valgus angle of the femur in northern Chinese adults.

The purpose of this study was to establish a method for measuring the knee valgus angle from the anatomical and mechanical axes on three-dimensional reconstruction imaging models, and to use this method for estimating an average knee valgus angle value for northern Chinese adults. Computed tomographic angiography data in DICOM format for 128 normal femurs from 64 adult subjects were chosen for analysis. After the femur images were subjected to three-dimensional reconstruction, the deepest point in the intercondylar notch (point A), the midpoint of the medullary cavity 20 cm above the knee-joint line (point B), and the landmark of the femoral head rotation center (point C) were identified on each three-dimensional model. The knee valgus angle was defined as the angle enclosed by the distal femoral anatomical axis (line AB) and the femoral mechanical axis (line AC). The average (mean±SD) of knee valgus angle for the 128 femurs was 6.20°±1.20° (range, 3.05° to 10.64°). Significant positive correlations were found between the knee valgus angles of the right and left sides and between the knee valgus angle and age. During total knee arthroplasty, choosing a valgus cut angle of approximately 6° may achieve a good result in reestablishing the natural mechanical alignment of the lower extremity for patients of northern Chinese ethnicity. Larger valgus cut angles should be chosen for older patients.