Microglia/physiology* ; Neurons/physiology* ; Cells, Cultured

Objective: To investigate the relationship of procollagen-lysine 2-oxoglutarate 5-dioxygenase 2 (PLOD2) expression and the clinical characteristics of osteosarcoma, and explore the potential mechanism of tumour metastasis promoted by PLOD2. Methods: The expression of PLOD2 in osteosarcoma tissues and paired adjacent tissues were detected by immunohistochemistry and qRT-PCR. Correlation of PLOD2 expression in osteosarcoma with the clinical pathologic features was analyzed by Chi square test and Kaplan-Meier analysis.Fibrillar collagen formation and collagen deposition in the tumor tissues were detected by picrosirius red staining. We transfected U-2OS cells with LV-vector, LV-over/PLOD2, sh-NC and sh-PLOD2. The expression of PLOD2 was detected by qRT-PCR. The impact of POLD2 on U-2OS cell invasion was determined by wound-healing assay and Transwell migration assay. The expressions of PLOD2/FAK/JAK2-STAT3 signal pathway related proteins were detected by western blotting. Results: The high expression level of PLOD2 in osteosarcoma tissues was 72.5%, significantly higher than 0% in paired adjacent noncancerous tissues (P<0.01), the expression of PLOD2 was positively correlated with lymph node metastasis, pulmonary metastasis and poor outcome (P<0.01). The same results were also observed in qRT-PCR assay. The median survival time of patients with high expression of PLOD2 protein was 13 months, significantly shorter than 32 months of patients with low expression of PLOD2 (P<0.05). The result of picrosirius red staining showed that the percentage of collagen fiber deposition in the osteosarcoma tissue with high level of PLOD2 was (74.43+ 9.63)%, significantly higher than (9.67±1.28)% in tissue with low expression of PLOD2 (P<0.001). The result of wound-healing and Transwell migration assay showed that over-expression of PLOD2 markedly promoted the invasion, however, knockdown of PLOD2 suppressed the invasion of U-2OS cells (both P<0.01). The result of western blotting showed that over-expression of PLOD2 significantly increased the expression levels of p-FAK, p-JAK2, p-STAT3, but knockdown PLOD2 decreased the levels of p-FAK, p-JAK2, p-STAT3 in U-2OS cells. Conclusions Up-regulation of PLOD2 in osteosarcoma is correlated with lymphatic and distant metastasis. PLOD2 promotes invasion and metastasis of osteosarcoma might through FAK/JAK2-STAT3 signal pathway.

Objective: To test the effect of metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) and/or osimertinib on the proliferation and apoptosis of HCC827 cells, and explore the potential mechanism of MALAT1 induced resistance to osimertinib. Methods: We transfected HCC827 cells with LV-vector or LV-over/MALAT1. Stable transfected cells (HCC827/Vector, HCC827/MALAT1) were selected by adding puromycin. HCC827/MALAT1 cells were further transfected with the shRNA-negative control (NC) or shRNA-human epidermal growth factor receptor 3 (ERBB3) plasmid. The effects of overexpression of MALAT1, knockdown of ERBB3 and/or osimertinib on the proliferation of HCC827 cells were evaluated by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. Cell apoptosis induced by MALAT1 overexpression, knockdown of ERBB3 and/or osimertinib treatment were analyzed by flow cytometry analysis. The expressions of EGFR and ERBB3 signal pathway related proteins in HCC827 cells treated with overexpression of MALAT1, knockdown of ERBB3 and/or osimertinib treatment were detected by western blot. Results: The MTT assay showed that sensitivity to osimertinib of HCC827/MALAT1 cells were significantly repressed. The 50% inhibitive concentration (IC₅₀) of osimertinib >4 000 nmol/L in HCC827/MALAT1 cells. However, knockdown of ERBB3 facilitated the anti-proliferation effect of osimertinib, and the IC₅₀ of osimertinib in shRNA-ERBB3 cells was (17.27±3.21) nmol/L. The results of flow cytometry analysis showed that the apoptotic rate of HCC827/MALAT1 cells induced by 10 nmol/L osimertinib was (8.38±0.92)%, significantly lower than (27.17±5.83)% of knockdown of ERBB3 (P<0.01). Western blotting showed that the expression of p-ERBB3, p-AKT and p-extracellular regulated protein kinases (ERK) in HCC827/MALAT1 cells was markedly up-regulated, while the expression of p-epithelial growth factor receptor (EGFR) was inhibited. The expressions of p-ERBB3, p-AKT and p-ERK were marginally affected by osimertinb. However, osimertinib downregulated the expressions of p-EGFR, p-ERBB3, p-AKT and p-ERK in ERBB3 deleted cells. Conclusions MALAT1 confers resistance to osimertinb in HCC827 cells by activating of the ERBB3/PI3K/AKT and ERBB3/MAPK/ERK signaling pathways.