Silencing the PIK3CA Gene Enhances the Sensitivity of Childhood Leukemia Cells to Chemotherapy Drugs by Suppressing the Phosphorylation of Akt

PURPOSE: This study aimed to investigate the effects of PIK3CA on the sensitivity of acute B lymphocytic leukemia cells (Nalm-6 cells) to chemotherapy drugs. MATERIALS AND METHODS: Children's normal B lymphocytes and Nalm-6 cells were cultured. Nalm-6 cells were transfected with PIK3CA siRNA (siPIK3CA group) or its negative control (PIK3CA-Control group). Normal Nalm-6 cells were named Mock group. Nalm-6 cells transfected by PIK3CA siRNA were treated with Akt inhibitor (siPIK3CA+Akti-1/2 group). mRNA and protein expression was detected by qRT-PCR and Western blot. Proliferation and sensitivity to chemotherapeutic drugs was detected by MTT assay. Cell cycle and apoptosis was explored by low cytometry. Transwell assay was performed to test invasion. RESULTS: PIK3CA mRNA (p=0.008) and protein (p=0.006) expression was higher in Nalm-6 cells than that in normal B lymphocytes. Compared with the Mock group and PIK3CA-Control group, Nalm-6 cells of the siPIK3CA group had lower OD495 values (all p < 0.05) and invasion cell numbers (p=0.03 and p=0.025), as well as a higher proportion of G0/G1 phase cells (p=0.020 and p=0.022), percentage of apoptosis (p=0.016 and p=0.022), and inhibition rate (all p < 0.05). pAkt expression in the siPIK3CA group (p=0.026 and p=0.031) and siPIK3CA+Akti-1/2 group (p=0.019 and p=0.023) was lower than that in the Mock group. CONCLUSION: PIK3CA silencing inhibited Nalm-6 cell proliferation and invasion, and promoted their apoptosis and sensitivity to chemotherapeutic drugs, potentially through regulation of the PI3K/AKT signaling pathway.

Apolipoprotein A-I mimetic peptide D4F protects macrophages from oxi-dized low-density lipoprotein-induced apoptosis by inhibiting caspase-12 / 中国病理生理杂志

[ABSTRACT]AIM:ToinvestigatetheeffectofD4F,anapolipoproteinA-Imimeticpeptide,onoxidizedlow-density lipoprotein ( ox-LDL)-induced macrophage apoptosis and activation of caspase-12, a key molecule in endoplasmic reticulum stress ( ERS )-associated apoptotic pathway, and to elucidate the underlying molecular mechanisms. METHODS:RAW264.7 macrophages were pretreated with D4F (12.5, 25 and 50 mg/L), 4-phenylbutyric acid (PBA, 5 mmol/L) or diphenyleneiodonium ( DPI, 5 μmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin ( TM, 4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and TUNEL detection, respective-ly.The levels of malondialdehyde ( MDA) and reactive oxygen species ( ROS) in the cells and the activities of superoxide dismutase ( SOD) and nicotinamide adenine dinucleotide phosphate ( NADPH) oxidase were determined.The protein level of caspase-12 was examined by Western blot analysis.RESULTS: Similar to the ERS inhibitor PBA, D4F protected RAW264.7 macrophages from ox-LDL or TM ( an ERS inducer)-induced decrease in the viability and increase in apoptotic rate in a dose-dependent manner.Like DPI (an oxidative stress inhibitor), D4F significantly inhibited ox-LDL-induced ox-idative stress, as expressed by the decreased generation of ROS and MDA ( P<0.01) , the increased activity of SOD and the decreased activity of NADPH oxidase (P<0.05).Moreover, similar to PBA and DPI, D4F significantly suppressed ox-LDL-induced activation of caspase-12 in a concentration-dependent manner ( P<0.05) .Furthermore, D4F also inhibi-ted the caspase-12 activation induced by TM (P<0.05).CONCLUSION: D4F inhibits macrophage apoptosis induced by ox-LDL, and the mechanism is at least partially by reducing oxidative stress and inhibiting the activation of caspase-12.

Case-control based study between polymorphisms in the adiponectin gene and polycystic ovary syndrome / 中华妇产科杂志

Objective To investigate the frequeney of four single nucleotide polymorphism (SNP) sites (rs17300539, rs12495941, rs2241766 and rs1501299) of adiponectin gene (ADIPOQ) and to elucidate its role in the pathogenesis of polycystic ovary syndrome (PCOS).Methods A total of 207 women with PCOS and 192 controls were recruited.Four ml whole-blood samples were collected in tubes containing ethylene diamine tetraacetic acid (EDTA) by peripheral venous puncture.Genomic DNA was extracted using a QIAamp DNA mini kit.Four SNP sites (rs17300539, rs12495941, rs2241766 and rs1501299) of ADIPOQ were amplified by PCR and then directly sequenced to screen variants.Results (1) The genotype frequencies of AA of rs17300539 in PCOS was significantly higher than controls [57.5％ (119/207) versus 48.4％ (93/192), P＜0.05].The genotype frequencies of AA of rs1501299 in PCOS was significantly lower than controls [4.8％ (10/207) versus 11.5％ (22/192), P＜0.05].While no significant differences were found in rs2241766 and rs12495941 (P＞0.05).(2) The allele A of rs17300539 [75.8％ (314/414)] and allele C frequeneies of rs1501299 [76.3％ (316/414)] in PCOS were significantly higher than controls [67.7％ (260/ 384), 69.0％ (265/384), respectively;all P＜0.05].While no significant differences were found in rs2241766 and rs12495941 (P＞0.05).(3) Further analysis we found rs17300539 AA genotypes had an increased risk for PCOS compared with GG genotype (OR=2.670, P=0.009), rs1501299 CC genotype had an increased risk for PCOS compared with AA genotypes (OR=2.756, P=0.012);and the difference remained significantly after adjustment for age, testosterone and body mass index (P＜0.05).Conclusions No signifi cant differences were observed in genotype and allele frequencies between PCOS and controls for rs2241766 and rs12495941.However, we observed an association between rs17300539, rs1501299 and PCOS.rs17300539 and rs1501299 of ADIPOQ perhaps are the susceptibility gene locus of PCOS.