Effect of CUL4A on the metastatic potential of lung adenocarcinoma to the bone.

Cullin 4A (CUL4A) is a member of the cullin family of proteins and has been demonstrated to be abnormally expressed in various types of malignancies. However, the function of CUL4A in metastasis of lung adenocarcinoma to the bone has rarely been reported. The aim of present of the study was to explore the biological functions and potential underlying molecular mechanisms of CUL4A in lung adenocarcinoma, highlighting a novel therapeutic target for the diagnosis and treatment of patients with lung adenocarcinoma. A549­CUL4A, H1299­CUL4A and H460­shCUL4A cells were created using lentiviral infection. The efficiency of knockdown or overexpression was assessed using reverse transcription­quantitative PCR and western blotting. The effects of CUL4A on proliferation, migration and invasion of lung adenocarcinoma cells in vitro and metastasis to the bone in vivo were determined using an MTT assay, colony formation assay, wound­healing assay, Transwell assay and a mouse model of bone metastasis. The relationship between CUL4A and the EMT­activator zinc finger E­box binding homeobox 1 (ZEB1) were detected by western blotting. The results showed that overexpression of CUL4A in lung adenocarcinoma cells increased proliferation, migration and invasion, and increased metastasis of A549 to the bones in vivo. Silencing of CUL4A expression in lung adenocarcinoma cells reduced proliferation, migration and invasion in vitro. Mechanistically, CUL4A transcriptionally upregulated expression of ZEB1 which resulted in epithelial­mesenchymal transition, which in turn promoted metastasis of lung adenocarcinoma to the bones. Taken together, these results suggest that CUL4A may serve an important regulatory role in the development of metastasis of lung adenocarcinoma to the bone.

Long Noncoding RNA H19 Participates in the Regulation of Adipose-Derived Stem Cells Cartilage Differentiation.

Adipose-derived stem cells (ADSCs) are multipotent and have received increasing attention for their applications in medicine. Cell-based therapies are optimal for diseases with loss or damage to tissues or organs. ADSCs and bone marrow mesenchymal stem cells (BMSCs) can differentiate into many cell lineages. Because of their advantages in accessibility and volume, ADSCs are regarded as a desirable alternative to BMSCs. In this study, we focused on the chondrocytic differentiation potential of ADSCs and the underlying mechanism. We found that the long noncoding RNA H19 plays an important role in this process. Overexpression of H19 in ADSCs induced differentiation towards chondrocytes. H19 is abundantly expressed during embryonic development and downregulated after birth, implying its regulatory role in determining cell fate. However, in our experiments, H19 exerted its regulatory function during cartilage differentiation of ADSCs through competing miRNA regulation of STAT2.

The role of GDF15 in bone metastasis of lung adenocarcinoma cells.

Lung cancer is the most common malignant tumor in China. It often metastasizes to bone, thereby significantly shortening the lives of patients, and reducing their quality of life. However, the efficacy of treatment for bone metastasis of lung cancer at this stage is very limited. The development and clinical application of molecular­targeted drugs for the effective targeted therapy of bone metastasis of lung cancer are urgently required. The growth differentiation factor 15 (GDF15) gene which may be associated with bone metastasis of lung cancer, was screened out by whole­genome sequencing. In the present study, we used a recombinant GDF15 lentivirus technique to upregulate the expression of GDF15 in lung adenocarcinoma A549 cells, and the results revealed that GDF15 could inhibit the proliferation, migration and invasion, while promoting apoptosis of A549 cells. In addition, GDF15 significantly decreased the number and sites of lung metastases and bone metastases in vivo compared to the control group. Finally, it was revealed that Smad2 and phospho­Smad2 protein expression was lower in the GDF15­overexpressing A549 cells. This result indicated that the tumor suppressive effect of GDF15 may be related to the TGF­ß/Smad signaling pathway, although more studies are still required for confirmation. In summary, GDF15 inhibited the growth and bone metastasis of lung adenocarcinoma A549 cells, and this effect may be achieved through the TGF­ß/Smad signaling pathway.