RESUMO
MicroRNAs (miRNAs or miRs) are small noncoding RNAs derived from genome to control target gene expression. Recently we have developed a novel platform permitting high-yield production of bioengineered miRNA agents (BERA). This study is to produce and utilize novel fully-humanized BERA/miR-328-3p molecule (hBERA/miR-328) to delineate the role of miR-328-3p in controlling nutrient uptake essential for cell metabolism. We first demonstrated successful high-level expression of hBERA/miR-328 in bacteria and purification to high degree of homogeneity (>98%). Biologic miR-328-3p prodrug was selectively processed to miR-328-3p to suppress the growth of highly-proliferative human osteosarcoma (OS) cells. Besides glucose transporter protein type 1, gene symbol solute carrier family 2 member 1 (GLUT1/), we identified and verified large neutral amino acid transporter 1, gene symbol solute carrier family 7 member 5 (LAT1/) as a direct target for miR-328-3p. While reduction of LAT1 protein levels by miR-328-3p did not alter homeostasis of amino acids within OS cells, suppression of GLUT1 led to a significantly lower glucose uptake and decline in intracellular levels of glucose and glycolytic metabolite lactate. Moreover, combination treatment with hBERA/miR-328 and cisplatin or doxorubicin exerted a strong synergism in the inhibition of OS cell proliferation. These findings support the utility of novel bioengineered RNA molecules and establish an important role of miR-328-3p in the control of nutrient transport and homeostasis behind cancer metabolism.
RESUMO
Objective To explore the effect of the use of flap transplantation combined with Masquelet tech-nique in the repair of long bone accompanied with soft tissue defect. Methods The retrospective study includes 16 cases of bone defects over 6.0 cm combined with soft tissue defect from March,2013 to March,2016,13 males and 3 females, of which the ages range from 16 to 65 years. The length of bone defect ranged from 6.0 to 12.0 cm, with an average of 8.5 cm,while the wound defect ranged from 5.2 cm×3.5 cm to 16.0 cm×7.5 cm. There were 8 cases out of 16 involve an infection:3 cases of Staphylococcus aureus(including 1 MRSA),2 cases of Staphylococcus epidermidis, 2 cases of Enterobacter cloacae, and 1 case of Acinetobacter baumannii. The 1 stage surgery in all patients admitted to hospital after complete debridement and external fixation, the clean wounds with bone defect received antibiotic-impregnated bone cement filling operation and a flap transplantation or transposition directly after the debridement, but the infected wounds received vacuum sealing drainage treatment firstly, associated with adequate use of antibi-otics for 1-2 weeks and then the bone cement filling and flap transplantation with infection totally controlled.After 8-12 weeks, we conducted the secondary internal fixation surgery replacing antibiotic-impregnated bone cement with autogenic cancellous bone, vancomycin artificial bone as well as rhBMP-2. All the cases were followed for 6 to 18 months. Results All patients with primary surgery are effectively controlled after 1-4 weeks of anti-infection treat-ment exclusive of the case with MRSA.As the condition of the patient with MRSA relapse,we changed to convention-al treatment: placed a continuous irrigation and suction equipment instead of the bone cement filling, the wound healed completely without fistula formation of osteomyelitis in 6 months after the treatment of Ilizarov technique. All transplantation and transposition flaps survived. As for those who received a secondary bone graft operation, all achieved a bony union in a period of 4-6 months. Conclusion The combination of flap transplantation and Masquelet technique is an effective method to repair limb long bone and soft tissue defect currently.