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Background The key enzymes of serine synthesis pathway (SSP) play an important role in tumor growth, proliferation, and invasion, but their roles in arsenic carcinogenesis are unclear. Objective To observe the effects of NaAsO2 treatment on the expressions of key enzymes [such as phosphoglycerate dehydrogenase (PHGDH), phosphoserine aminotransferase 1 (PSAT1), and phosphoserine phosphatase (PSPH)] of SSP and on the ability to proliferate and migrate in human immortalized skin keratinocytes (HaCaT) and NaAsO2-induced malignantly transformed HaCaT (T-HaCaT), and to explore the roles of SSP key enzymes in arsenic carcinogenesis. Methods (1) The T-HaCaT cells constructed earlier by our research team were divided into a passage control (0 μmol·L−1 NaAsO2) group, a T-HaCaT (0.5 μmol·L−1 NaAsO2) group, a NCT503 (PHGDH inhibitor, 25 μmol·L−1) group, and a NCT503 (25 μmol·L−1) + T-HaCaT (0.5 μmol·L−1 NaAsO2) group. Western blotting was used to detect the protein expression levels of SSP key enzymes in the passage control group and the T-HaCaT group. CCK8 assay and cell scratch test were used to detect the proliferation and migration rates of cells in each group respectively. (2) Well-grown logarithmic-phase HaCaT cells were treated with 0, 0.625, 1.25, and 2.5 μmol·L−1 NaAsO2 for 0, 24, 48, and 72 h to detect cell proliferation rate and protein expression levels of SSP key enzymes. In the subsequent experiment, HaCaT cells were pretreated with 25 μmol·L−1 NCT503 for 6 h, and then treated with 2.5 μmol·L−1 NaAsO2 for 72 h continuously. The experimental groups included a control (0 μmol·L−1 NaAsO2) group, an exposure (2.5 μmol·L−1 NaAsO2) group, a pretreatment (25 μmol·L−1 NCT503) group, and a pretreatment (25 μmol·L−1 NCT503) + exposure (2.5 μmol·L−1 NaAsO2) group, to detect the proliferation rate of cells in each group. Results The protein expression level of PHGDH in the T-HaCaT group were 1.60 times higher than that in the passage control group (P<0.05), and its proliferation rate (177.51%±14.69%) and migration rate (53.85%±0.94%) were also higher than the passage control group’s (100.00%±0.00% and 24.30%±2.26%) (both Ps<0.05), respectively. After the NCT503 intervention, the proliferation rate (144.97%±8.08%) and migration rate (35.80%±0.99%) of cells in the NCT503 + T-HaCaT group were lower than those in the T-HaCaT group (both P<0.05). The proliferation rate of HaCaT cells after NaAsO2 exposure for 72 h increased with the increase of exposure concentration (r=0.862, P<0.05), and consistently, the protein levels of SSP key enzymes in HaCaT cells in each exposure group were higher than those in the control group (all P<0.05). The proliferation rate of HaCaT cells treated with 2.5 μmol·L−1 NaAsO2 increased with the extension of exposure time (r=0.775, P<0.05), which was consistent with the changes of PHGDH levels in cells. After the NCT503 intervention, the proliferation rate of the pretreatment + exposure group was significantly lower than that of the exposure group (P<0.05). Conclusion The key enzymes of SSP may play an important role in the proliferation of T-HaCaT cells induced by NaAsO2.
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Objectives: To investigate the expression of phosphoserine aminotransferase 1 (PSAT1) in pancreatic cancer tissues, and its potential role in pancreatic cancer. Methods: The expression of PSAT1 in 98 human pancreatic cancer tissues, which were collected from the People＇s Hospital of Guizhou, between July 2013 to July 2017, and the corresponding adjacent normal tissues was analyzed by immunohistochemical staining. Additionally, the relationship between the expression of PSAT1 and the clinicopathological parame-ters, overall survival (OS), and disease-free survival (DFS) of patients with pancreatic cancer was evaluated. The human pancreatic can-cer cell lines, BxPC-3 and SW1990, were transfected with PSAT1-siRNA, to investigate the effect of PSAT1 knockdown on cell prolifera-tion, migration, and invasion. Additionally, we performed Western blot to assess the expression of PI3K/Akt/mTOR-related proteins in PSAT1-knockdown cells. Results: The percentages of PSAT1-positive cells in pancreatic cancer and adjacent non-tumor tissues were 69.4% (68/98) and 5.0% (5/98), respectively, indicating a significantly higher expression of PSAT1 in pancreatic cancer tissues com-pared to adjacent non-tumor tissues (P<0.05). The increased expression of PSAT1 in pancreatic cancer tissues correlated with lymph node metastasis and TNM stage. Kaplan-Meier analysis suggested that a high expression of PSAT1 correlated with a poor OS and DFS compared to a low expression of PSAT1 (P<0.05). Cox regression analysis showed that the expression of PSAT1 is an independent prog-nostic marker for OS and DFS in pancreatic cancer patients (P<0.05, all). Transient transfection of BxPC-3 and SW1990 cells with PSAT1-siRNA markedly reduced the cell proliferation, migration, and invasion abilities of these cells compared to transfection with NC-siRNA (P<0.05). Knockdown of PSAT1 in pancreatic cancer cells also inhibited the expression of p-Akt and p-mTOR (P<0.05). Conclusions: The expression of PSAT1 increases in human pancreatic cancer tissues and cell lines. Additionally, PSAT1 regulates cell proliferation and in-vasion through the PI3K/Akt/mTOR pathway.
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ObjectiveTo detect the association between schizophrenia and polymorphism of phosphoserine aminotransferase 1 ( PSAT1 ) gene.MethodsThe study group included 158 patients with schizophrenia from Xi' an Mental Health Center and the control group included 316 parents.The polymorphism of rs69287125,rs137824326 of phosphoserine aminotransferase 1 gene was detected with PCR methods and SNP typing in all nucleus families by correlation analysis and haplotype relative risk analysis.ResultsThe rs69287125 allele was associated with schizophrenia (P=0.011 ),the G allele was protective factor (Z =-2.31 ) and the A allele was hazarding factor (Z =2.31 ).The rs137824326 allele was associated with schizophrenia (P=0.007 ),the G allele was protective factor ( Z =- 2.54) and the A allele was the hazarding factor( Z =2.54).The haplotypes of A/A and G/G in the rs69287125-rs137824326 were associated with schizophrenia (P =0.021,0.015,Z =2.16,- 1.85).ConclusionThe polymorphism of phosphoserine aminotransferase 1 gene is associated with schizophrenia in Chinese.