Mitochondrial carrier homolog 2 increases malignant phenotype of human gastric epithelial cells and promotes proliferation,invasion,and migration of gastric cancer cells

BACKGROUND The precise role of mitochondrial carrier homolog 2(MTCH2)in promoting malignancy in gastric mucosal cells and its involvement in gastric cancer cell metastasis have not been fully elucidated.AIM To determine the role of MTCH2 in gastric cancer.METHODS We collected 65 samples of poorly differentiated gastric cancer tissue and adjacent tissues,constructed MTCH2-overexpressing and MTCH2-knockdown cell models,and evaluated the proliferation,migration,and invasion of human gastric epithelial cells(GES-1)and human gastric cancer cells(AGS)cells.The mito-chondrial membrane potential(MMP),mitochondrial permeability transformation pore(mPTP)and ATP fluorescence probe were used to detect mitochondrial function.Mitochondrial function and ATP synthase protein levels were detected via Western blotting.RESULTS The expression of MTCH2 and ATP2A2 in gastric cancer tissues was significantly greater than that in adjacent tissues.Overexpression of MTCH2 promoted colony formation,invasion,migration,MMP expression and ATP production in GES-1 and AGS cells while upregulating ATP2A2 expression and inhibiting cell apoptosis;knockdown of MTCH2 had the opposite effect,promoting overactivation of the mPTP and promoting apoptosis.CONCLUSION MTCH2 can increase the malignant phenotype of GES-1 cells and promote the proliferation,invasion,and migration of gastric cancer cells by regulating mitochondrial function,providing a basis for targeted therapy for gastric cancer cells.

Toward genetic transformation of mitochondria in mammalian cells using a recoded drug-resistant selection marker

Due to technical difficulties,the genetic transformation of mitochondria in mammalian cells is still a challenge.In this report,we described our attempts to transform mammalian mitochondria with an engineered mitochondrial genome based on selection using a drug resistance gene.Because the standard drug-resistant neomycin phosphotransferase confers resistance to high concentrations of G418 when targeted to the mitochondria,we generated a recoded neomycin resistance gene that uses the mammalian mitochondrial genetic code to direct the synthesis of this protein in the mitochondria,but not in the nucleus（mitochondrial version）.We also generated a universal version of the recoded neomycin resistance gene that allows synthesis of the drug-resistant proteins both in the mitochondria and nucleus.When we transfected these recoded neomycin resistance genes that were incorporated into the mouse mitochondrial genome clones into mouse tissue culture cells by electroporation,no DNA constructs were delivered into the mitochondria.We found that the universal version of the recoded neomycin resistance gene was expressed in the nucleus and thus conferred drug resistance to G418 selection,while the synthetic mitochondrial version of the gene produced no background drug-resistant cells from nuclear transformation.These recoded synthetic drug-resistant genes could be a useful tool for selecting mitochondrial genetic transformants as a precise technology for mitochondrial transformation is developed.