Effect of AMPK pathway on apoptosis of human thyroid papillary cancer B-CPAP cells under low glucose and hypoxia conditions through CPT1c regulated by PPARα / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the mechanisms of carnitine palmitoyltransferase 1c (CPT1c) expression to affect the proliferation and apoptosis of human thyroid papillary cancer B-CPAP cells through the AMP-dependent/activated protein kinase (AMPK) pathway in the low glucose and hypoxic conditions. Methods: Firstly,humanthyroidpapillarycarcinomaB-CPAP cells were cultured under normal condition or low glucose and hypoxic condition respectively, followed with the treatment of AMPK inhibitor compound C. Western blotting was used to detect the expressions of AMPK, p-AMPK, peroxisome proliferator-activated receptor α (PPARα) and CPT1c; the proliferation and apoptosis were detected by CCK-8 and Flow cytometry, respectively. Then PPARα-siRNA was synthesized and transfected into B-CPAP cells to knock down PPARα, and then the cells were cultured under normal or low glucose and hypoxic condition respectively.Above indicators were also detected to verify the regulation of PPARα on CPT1c. Finally, the human luciferase reporter plasmid containing CPT1c gene promoter was constructed, and the effect of PPARα on the activity of CPT1c promoter luciferase activity was observed by immunofluorescence. Results: The expressions ofAMPK, p-AMPK, PPARα and CPT1c were significantly increased in B-CPAP cells under low glucose and hypoxia condition (P<0.05 or P<0.01), while cell proliferation and apoptosis rate did not change significantly (P>0.05). After the treatment of AMPK inhibitor compound C, the expressions of p-AMPK, PPARα and CPT1c in low glucose and hypoxia group were significantly decreased (P<0.05 or P<0.01), the inhibitory rate on cell proliferation and apoptosis rate were significantly increased (P<0.05). However, the change range was smaller than that in the normal culture + compound C group (P<0.05).After PPARα knockdown, the expressions ofAMPK, p-AMPK, PPARα and CPT1c in cancer cells cultured under normal conditions were significantly decreased (P<0.05 or P<0.01), and the inhibitory rate on cell proliferation and apoptosis rate were significantly increased (P<0.05). While under low glucose and hypoxia condition, the expression of CPT1c in cells after transfection was significantly decreased (P<0.05), and the inhibition rate on cell proliferation and the apoptosis rate were significantly increased (P<0.05); However, the change range was still lower than that of normal condition group after transfection (P<0.05).After PPARα overexpression, the ratio of fluorescence in the empty vector group was not significantly different from that of the blank group (P>0.05), and the ratio of fluorescence was significantly increased in PPARα over-expression group (P<0.05). Conclusions: AMPK can increase the expression of PPARα to promote the expression of CPT1c in thyroid cancer B-CPAP cells under low glucose and hypoxia conditions, thereby inhibiting cell apoptosis and maintaining cell proliferation ability.

Research progress of carnitine palmitoyltransferase 1in tumor immunotherapy / 药学学报

Carnitine palmitoyltransferase 1 (CPT1) is a fatty acid β-oxidative rate-limiting enzyme of fatty acid β-oxidation (FAO) present in the outer membrane of mitochondria, which is closely related to metabolic diseases and tumors. Numerous studies have shown that various subtypes of CPT1 are abnormally expressed in cancer cells and play an important role in resistance to metabolic stress. With the development of tumor immunotherapy, its role in immune cells and organs has also attracted attention. This article aims to review the biological functions of CPT1 and the role of different subtypes in tumor metabolism and immune regulation, and the research progress of its inhibitors, providing new ideas for cancer treatment.

Novel Mutations in the CPT1A Gene Identified in the Patient Presenting Jaundice as the First Manifestation of Carnitine Palmitoyltransferase 1A Deficiency / 대한소아소화기영양학회지

Carnitine palmitoyltransferase 1A (CPT1A) is an enzyme functioning in mitochondrial fatty acid oxidation (FAO) of the liver. Patients with CPT1A deficiency have impaired mitochondrial FAO and display hypoketotic hypoglycemia and hepatic encephalopathy as typical manifestations. In this report, we present a case of CPT1A deficiency presenting jaundice as the first manifestation. A 1.9 years old boy showed jaundice and elevated levels of free and total carnitine were observed. From direct sequencing analysis of CPT1A, two novel mutations, c.1163+1G>A and c.1393G>A (p.Gly465Arg), were identified. At the age of 2.2 years, hypoglycemia, tachycardia, and altered mental status developed just after cranioplasty for craniosynostosis. High glucose infusion rate was required for recovery of his vital signs and mentality. Diet rich in high carbohydrate, low fat and inclusion of medium chain triglyceride oil resulted in improvement in cholestatic hepatitis and since then the boy has shown normal growth velocity and developmental milestones to date.

Effect of hydrogen sulfide on hepatic lipid accumulation in obese mice / 中国药理学通报

Aim To investigate the effect of hydrogen sulfide on hepatic lipid accumulation in obese mice. Methods C57 BL/6 J mice were randomly divided into control group, model group, and NaHS group. The mice of the control group were fed with normal diet. The mice of the model group and the NaHS group were fed with high-fat diet. From the thirteenth week, the mice of NaHS group were injected intraperitoneally with NaHS (H2S donor) in a dose of 50 μmol·kg-1 per day for 4 weeks and the mice of the model group were injected with the same volume of saline. All mice were sacrificed at the end of the 16th week. The tis-sues of liver were homogenized and centrifugated. The supernatants were used for the determination of triglyc-eride and cholesterol in liver. The morphology of liver was tested by H&E staining. Liver lipid accumulation was determined by oil red staining. Total RNA was ex-tracted from frozen tissue of liver. PCR was used to de-tect CPT-1 , FAS gene expression and ELISA method was used to detect CPT-1,FAS activity in mice liver. Results The body weight of the mice from NaHS group and model group was bigger than that of the mice from control group. Compared with the model group, the body weight of the mice from NaHS group was less;the content of triglyceride and cholesterol in liver was lower; the degree of liver tissue pathological changes and lipid accumulation were alleviated; CPT-1 expres-sion and activity were increased; FAS expression and activity were decreased. Conclusions These data in-dicate that hydrogen sulfide can reduce the lipid con-tent of liver tissue in obese mice and alleviate fatty liv-er. The mechanism may be associated with the in-creased expression of CPT-1 and the decreased expres-sion of FAS in liver.

Effect of different targets of glucose control on liver damage in rats with sepsis / 中国感染与化疗杂志

Objective To examine the effect and mechanism of different targets of glucose control on liver damage in rats with sepsis .Methods The rat sepsis model was established by cecal ligation and puncture (CLP) .Forty Sprague‐Dawley rats were randomly divided into five groups (eight rats to each group):sham operation (sham group) ,sepsis (CLP group) ,glycemic control A group (glucose target 4 .6‐6 .1 mmol/L ) ,glycemic control B group (glucose target 6 .2‐8 .3 mmol/L ) and glycemic control C group (glucose target 8 .4‐10 .0 mmol/L) .The animals were sacrificed 12 hours after CLP .Venous blood was sampled for testing alanine transaminase (ALT ) , aspartate transaminase (AST ) and free fatty acid (FFA ) . Peroxisome proliferator activated receptor‐α (PPAR‐α) and liver carnitine palmitoyltransferase 1 (CPT‐1 ) protein were determined by immunohistochemistry .The pathological changes of liver tissue was observed under an optical microscope .Results The levels of ALT ,AST and FFA in venous blood and the pathological tissue injury score in sepsis groups were higher than those in sham group and all glycemic control groups (P0 .05) .The levels of PPARαand liver CPT‐1 were significantly higher in group A than in group B or group C (P<0 .05) ,and lower in group C than in group B(P<0 .05) .Conclusions The lowest target of glucose control(4 .6‐6 .1 mmol/L)shows better protective effects on liver damage in rats with sepsis ,the mechanism of which may be related to upregulation of PPARα and liver CPT‐1 expression .