MicroRNA-34a inhibits tumor invasion and metastasis in osteosarcoma partly by effecting C-IAP2 and Bcl-2.

Osteosarcoma is a common primary malignant bone tumor that occurs mainly in children and adolescents. Recent evidence has demonstrated that miR-34a is involved in the invasion and metastasis of osteosarcoma. This study aims to explore the effect of biological behavior of miR-34a on osteosarcoma. First, we collect osteosarcoma and adjacent specimens, and the relative expression of miR-34a and C-IAP2 messenger RNA was quantitated by real-time polymerase chain reaction. Furthermore, miR-34a stimulant is synthesized and transfected onto osteosarcoma MG-63 cells. The effect of overexpression of miR-34a on osteosarcoma was detected by colony-forming assay, Annexin V-fluorescein isothiocyanate Apoptosis Detection Kit I, Transwell assay, and animal experiment in vivo. Finally, the relative levels of C-IAP2 and Bcl-2 protein were checked by western blot, and the activity of caspase-3 and caspase-9 was tested by spectrophotometry assay. In conclusion, miR-34a was downregulated in osteosarcoma cells. And the expression of C-IAP2 and Bcl-2 protein was drastically inhibited, and the activities of caspase-3 and caspase-9 were significantly increased after transfecting miR-34a onto osteosarcoma MG-63 cells. And the overexpression of miR-34a can inhibit cell invasion and metastasis, promote cell apoptosis, and arrest cells in G0/G1 period. And the animal experiment in vivo demonstrated that the overexpression of miR-34a could significantly inhibit the growth of osteosarcoma in animal skin. Taken together, we indicated that miR-34a can inhibit tumor invasion and metastasis in osteosarcoma, and its mechanism may be partly related to downregulating the expression of C-IAP2 and Bcl-2 protein directly or indirectly.

Characteristics of psychrophilic bacterial communities and associated metabolism pathways in different environments by a metagenomic analysis.

Psychrophilic bacteria, the dominant spoilage organisms in raw milk, secrete heat-stable extracellular proteases and lipases that lead to the decomposition of milk and dairy products. In this study, we investigated psychrophilic bacteria in 165 raw milk samples collected across four seasons and six regions in China using shotgun metagenomic sequencing and traditional culture methods. The isolated psychrophilic bacteria were classified into 40 genera and 185 species. Pseudomonas was the most prevalent, accounting for 51.13 % of the genera, while Lactococcus and Chryseobacterium were also notably abundant (> 6.0 %). Metagenomic sequencing revealed that Pseudomonas (47.9 %), Stenotrophomonas (9.75 %), Sphingomonas (6.73 %), Latilactobacillus (6.38 %) and Lactococcus (5.16 %) were the dominant genera in the raw milk samples. The diversity of psychrophilic bacteria in raw milk was strongly influenced by seasonal variations, with the sampling region being a less significant factor. KEGG annotation indicated that carbohydrate and amino acid metabolism were the primary metabolic pathways in these bacteria. Metagenomic sequencing not only accurately identifies species but also provides functional insights into psychrophilic bacteria in raw milk, aiding in understanding their activities, promoting their control on farms, and ultimately improving raw milk quality.