Different effects of phosphatidylinositol 3-kinase inhibitor LY294002 and Akt inhibitor SH-5 on cell cycle progression in synchronized HL-60 leukemia cells

Background and Purpose: Pharmacological inhibitors of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway have been proposed in treatment of leukemia. Our previous studies demonstrated that PI3K inhibitor LY294002 and Akt inhibitor SH-5 reduced the number of viable HL-60 leukemia cells, but exerted different effects on their differentiation. PI3K inhibitor LY294002 induced an arrest of HL-60 cells in G0/G1 and G2/M phases of the cell cycle, but the effects of Akt inhibitor on cell cycle progression have not been investigated. The present study was undertaken in order to compare the effects of LY294002 and SH-5 on cell cycle progression in a model of aphidicolin and nocodazole-synchronized HL-60 cells. Materials and Methods: HL-60 cells were arrested at G1/S phase by aphidicolin, or G2/M phase by nocodazole, washed and allowed to progress synchronously through the cell cycle. PI3K inhibitor LY294002 (10 μM) and Akt inhibitor SH-5 (20 μM) were added to medium after release from the block. DNA content was determined by propidium iodide staining and flow cytometry. Results: In aphidicolin-synchronizedHL-60 cells, LY294002 induced a delay in progression through S andG2/M phases, while Akt inhibitor had no significant effects. No statistically significant effects were observed in LY294002 or SH-5-treated cells at 1–5 h after release from nocodazole block. Conclusion: PI3K inhibitor LY294002 and Akt inhibitor SH-5, applied at doses that effectively inhibit Akt-activity, have different effects on cell cycle progression in aphidicolin-synchronized HL-60 cells, suggesting that LY294002-induced delay in S and G2/M phase is probably not due to the specific inhibition of Akt-activity

The Antimetastatic Effect of Macrophages Restored by Indomethacin: Concomitant Tumor Immunity Model

The role of macrophages acting as immunologic antitumor effectors and promoters of tumor growth are poorly understood as yet. We investigated the role of macrophage in model of concomitant immunity (CI), a phenomenon of secondary tumor rejection during the primary tumor growth. It has been shown that the period of CI weakening can coincide with appearance of tumor metastases. We used mammary carcinoma (MC) artificial lung metastases to evaluate the influence of macrophages from various period of CI on the development of metastases in mice. Our results indicated that macrophages are responsible for the late period of CI weakening and suppression. To investigate weather prostaglandins can mediate suppressive effect of macrophages we used experiments with indomethacin and we found that inhibition of prostaglandin E2 synthesis by indomethacin restored antimetastatic effect of concomitant immune macrophages

The Association of Essential Metals with APOE Genotype in Alzheimer’s Disease

Background: The major confirmed genetic risk factor for late-onset, sporadic Alzheimer's disease (AD) is variant ɛ4 of apolipoprotein E gene (APOE). It is proposed that ApoE, a protein involved in transport of cholesterol to neurons can cause neurodegeneration in AD through interaction with metals. Previous studies mostly associated copper, iron, zinc, and calcium with ApoE4-mediated toxicity. ----- Objective: To test the association of essential metals with APOE genotype. ----- Methods: We compared plasma and cerebrospinal fluid (CSF) levels of copper, zinc, iron, sodium, magnesium, calcium, cobalt, molybdenum, manganese, boron, and chromium, and CSF ferritin levels among AD, mild cognitive impairment (MCI) patients, and healthy controls (HC) with different APOE genotype. ----- Results: Sodium, copper, and magnesium levels were increased in carriers of ɛ4 allele. Additionally, the increase in sodium, calcium and cobalt plasma levels was observed in carriers of ɛ4/ɛx genotype. The decrease in boron plasma levels was observed in carriers of ɛ4 allele and ɛ4/ɛ4 genotype. Additionally, CSF zinc levels as well as plasma sodium levels were increased in AD patients compared to HC. ----- Conclusion: These results indicate that the molecular underpinnings of association of essential metals and metalloids with APOE should be further tested and clarified in vivo and in vitro