Purpose:Accumulative evidence suggests that folate has a protective effect on gastric cancer. The methylenetetrahyd-rofolate dlehydrogenase(MTHFD) plays an important role in folate and homocysteine metabolisms, and po...Purpose:Accumulative evidence suggests that folate has a protective effect on gastric cancer. The methylenetetrahyd-rofolate dlehydrogenase(MTHFD) plays an important role in folate and homocysteine metabolisms, and polymorphisms of MTHFD may result in disturbance of the folate-mediated homocysteine pathway. The aim of this study is to test the hypothesis that genetic variants of MTHFD and plasma homocysteine levels are associated with risk of gastric cancer and modulated by genotypes of methylenetetrahydrofolate reductase(MTHFR). Experimental Design: We genotyped G1958A and T401C in MTHFD and C677T in MTHFR and detected total plasma homocysteine(tHcy) levels in a case-control study of 589 gastric cancer cases and 635 cancer-free controls in a high-risk Chinese population. Results:The variant genotypes of MTHFD 1958AA and 401CC were associated with a significantly increased risk of gastric canceradjusted odds ratio(OR), 2.05; 95% confidence interval(95% CI),1.34-3.13 for 1958AA; adjusted OR,1.43; 95% CI,1.14-1.80 for 401CC compared with 1958GG/GA and 401TT/TC genotypes, respectively. Both of the effects were more evident in the subjects carrying MTHFR 677CT/TT genotypes. The average tHcy level was significantly higher in gastric cancer cases than in controls(P < 0.01), and the upper quartile of tHcy (> 13.6 mu mol/L) was associated with an 82% significantly increased risk of gastric cancer, compared with the lowest quartile of tHcy(<= 8.0 pmol/L;adjusted OR,1.82; 95% CI,1.20-2.75). Conclusions:The strong associations between MTHFD variants and the plasma tHcy levels and gastric cancer risk suggest, for the first time, a possible gene-environment interaction between genetic variants of folate-metabolizing genes and high tHcy levels in gastric carcinogenesis.展开更多
Folate metabolism plays an essential role in tumor development.Various cancers display therapeutic response to reagents targeting key enzymes of the folate cycle,but obtain chemoresistance later.Therefore,novel target...Folate metabolism plays an essential role in tumor development.Various cancers display therapeutic response to reagents targeting key enzymes of the folate cycle,but obtain chemoresistance later.Therefore,novel targets in folate metabolism are highly demanded.Methylenetetrahydrofolate dehydrogenase/methylenetetrahydrofolate cyclohydrolase 2(MTHFD2)is one of the key enzymes in folate metabolism and its expression is highly increased in mutiple human cancers.However,the underlying mechanism that regulates MTHFD2 expression remains unknown.Here,we elucidate that SIRT4 deacetylates the conserved lysine 50(K50)residue in MTHFD2.K50 deacetylation destabilizes MTHFD2 by elevating cullin 3 E3 ligase-mediated proteasomal degradation in response to stressful stimuli of folate deprivation,leading to suppression of nicotinamide adenine dinucleotide phosphate production in tumor cells and accumulation of intracellular reactive oxygen species,which in turn inhibits the growth of breast cancer cells.Collectively,our study reveals that SIRT4 senses folate availability to control MTHFD2 K50 acetylation and its protein stability,bridging nutrient/folate stress and cellular redox to act on cancer cell growth.展开更多
文摘Purpose:Accumulative evidence suggests that folate has a protective effect on gastric cancer. The methylenetetrahyd-rofolate dlehydrogenase(MTHFD) plays an important role in folate and homocysteine metabolisms, and polymorphisms of MTHFD may result in disturbance of the folate-mediated homocysteine pathway. The aim of this study is to test the hypothesis that genetic variants of MTHFD and plasma homocysteine levels are associated with risk of gastric cancer and modulated by genotypes of methylenetetrahydrofolate reductase(MTHFR). Experimental Design: We genotyped G1958A and T401C in MTHFD and C677T in MTHFR and detected total plasma homocysteine(tHcy) levels in a case-control study of 589 gastric cancer cases and 635 cancer-free controls in a high-risk Chinese population. Results:The variant genotypes of MTHFD 1958AA and 401CC were associated with a significantly increased risk of gastric canceradjusted odds ratio(OR), 2.05; 95% confidence interval(95% CI),1.34-3.13 for 1958AA; adjusted OR,1.43; 95% CI,1.14-1.80 for 401CC compared with 1958GG/GA and 401TT/TC genotypes, respectively. Both of the effects were more evident in the subjects carrying MTHFR 677CT/TT genotypes. The average tHcy level was significantly higher in gastric cancer cases than in controls(P < 0.01), and the upper quartile of tHcy (> 13.6 mu mol/L) was associated with an 82% significantly increased risk of gastric cancer, compared with the lowest quartile of tHcy(<= 8.0 pmol/L;adjusted OR,1.82; 95% CI,1.20-2.75). Conclusions:The strong associations between MTHFD variants and the plasma tHcy levels and gastric cancer risk suggest, for the first time, a possible gene-environment interaction between genetic variants of folate-metabolizing genes and high tHcy levels in gastric carcinogenesis.
基金supported by the National Key R&D Program of China(2020YFA0803400/2020YFA0803402 and 2019YFA0801703 to Q.-Y.L.)the National Natural Science Foundation of China(81872240 to M.Y.,82002951 to J.L,and 81790250/81790253,91959202,and 82121004 to Q.-Y.L.)the Innovation Program of Shanghai Municipal Education Commission(N173606 to Q.-Y.L.).
文摘Folate metabolism plays an essential role in tumor development.Various cancers display therapeutic response to reagents targeting key enzymes of the folate cycle,but obtain chemoresistance later.Therefore,novel targets in folate metabolism are highly demanded.Methylenetetrahydrofolate dehydrogenase/methylenetetrahydrofolate cyclohydrolase 2(MTHFD2)is one of the key enzymes in folate metabolism and its expression is highly increased in mutiple human cancers.However,the underlying mechanism that regulates MTHFD2 expression remains unknown.Here,we elucidate that SIRT4 deacetylates the conserved lysine 50(K50)residue in MTHFD2.K50 deacetylation destabilizes MTHFD2 by elevating cullin 3 E3 ligase-mediated proteasomal degradation in response to stressful stimuli of folate deprivation,leading to suppression of nicotinamide adenine dinucleotide phosphate production in tumor cells and accumulation of intracellular reactive oxygen species,which in turn inhibits the growth of breast cancer cells.Collectively,our study reveals that SIRT4 senses folate availability to control MTHFD2 K50 acetylation and its protein stability,bridging nutrient/folate stress and cellular redox to act on cancer cell growth.
