Role of lipid polymorphism in G protein-membrane interactions: Nonlamellar-prone phospholipids and peripheral protein binding to membranes

Self Cite

154

Reduced brain levels of long chain polyunsaturated fatty acids[arachidonic acid and docosahexanoic acid (DHA)] are observed in elderly subjects and patients with Alzheimer's disease. To determine the effects of n-3 fatty acids on aged rat brain, 2-year-old rats were fed fish oil (27% DHA content) for 1 month, and gene expression analysis and fatty acid and molecular species composition of the major phospholipid species were assessed. No significant alteration could be observed in the fatty acid composition of ethanolamine phosphoglycerides and phosphatidylserines with the exception of DHA, which was slightly higher in brains of rats receiving fish oil. However, a drastic reduction in arachidonic acid in phosphatidylinositoles was observed. The expression of 23 genes was altered in response to fish oil feeding in the hippocampus. The transcription of transthyretin (TTR) was induced by 10-fold as evidenced by microarray analysis and confirmed by real-time quantitative RT-PCR. Expression of IL-1 and NO synthase, which has been implicated in the prevention of neurological diseases, was unaltered. TTR is an amyloid ␤ protein scavenger, so an increase in its expression could prevent amyloid aggregate formation. We believe the beneficial effects of fish oil might be common to other agents, i.e., induce TTR expression, like nicotine and Ginkgo biloba extract.

Section: Discussionsupporting

confidence: 56%

Short-term administration of omega 3 fatty acids from fish oil results in increased transthyretin transcription in old rat hippocampus

Puskás

Kitajka

Nyakas

et al. 2003

Self Cite

154

“…In line with these results, the addition of SM to culture medium enhances gemcitabine-mediated pancreatic cancer cell death (29) further indicating the relevance of this lipid in cancer cell survival. On the other hand, 2OHOA treatments induced specific changes in the levels of other membrane lipids (DAG, PE, and 2OHOA) that contributed to remodel membrane microdomains and regulated glioma cell signaling (30)(31)(32). These changes also facilitated the membrane binding and activation of PKCα (4, 10, and Fig.…”

Section: Discussionmentioning

confidence: 99%

2-Hydroxyoleate, a nontoxic membrane binding anticancer drug, induces glioma cell differentiation and autophagy

Terés

Lladó

Higuera

et al. 2012

Self Cite

115

Despite recent advances in the development of new cancer therapies, the treatment options for glioma remain limited, and the survival rate of patients has changed little over the past three decades. Here, we show that 2-hydroxyoleic acid (2OHOA) induces differentiation and autophagy of human glioma cells. Compared to the current reference drug for this condition, temozolomide (TMZ), 2OHOA combated glioma more efficiently and, unlike TMZ, tumor relapse was not observed following 2OHOA treatment. The novel mechanism of action of 2OHOA is associated with important changes in membrane-lipid composition, primarily a recovery of sphingomyelin (SM) levels, which is markedly low in glioma cells before treatment. Parallel to membrane-lipid regulation, treatment with 2OHOA induced a dramatic translocation of Ras from the membrane to the cytoplasm, which inhibited the MAP kinase pathway, reduced activity of the PI3K/Akt pathway, and downregulated Cyclin D-CDK4/6 proteins followed by hypophosphorylation of the retinoblastoma protein (RB). These regulatory effects were associated with induction of glioma cell differentiation into mature glial cells followed by autophagic cell death. Given its high efficacy, low toxicity, ease of oral administration, and good distribution to the brain, 2OHOA constitutes a new and potentially valuable therapeutic tool for glioma patients.fatty acids | sphingomyelin synthase | cancer drug target | glioma biomarker C ancer cells of undifferentiated phenotype (e.g., glioma) have a poor prognosis and limited treatment options. Primary brain tumors, of which glioma is the most common, are generally associated with very high rates of mortality (ca. 90%), being the median survival of patients about 1 y (1, 2). Chemotherapy provides only modest benefits to radiotherapy and surgery being the alkylating agent temozolomide (TMZ) the reference drug; however, tumor relapse is usually observed, and TMZ only increases the patients' life expectancy about 2.5 m (from 12.1 to 14.6 m: ref.3). The present study was designed to investigate the efficacy of 2OHOA against glioma and its molecular mechanisms of action. 2OHOA exhibited a greater efficacy than TMZ in the treatment of glioma, and there was no relapse after long-term treatment with 2OHOA. This efficacy and lack of toxicity at therapeutic doses has been acknowledged recently by the European Medicines Agency (EMA) to designate 2OHOA orphan drug for the treatment of glioma. In previous studies, we showed that this compound induces cell cycle arrest of lung cancer cells (4-6). Here, we showed that 2OHOA reversed the altered lipid profile of glioma cells and how this modification regulated cell signaling to induce autophagy specifically in glioma but not normal cells.Moreover, in the present study we demonstrated that the changes induced by 2OHOA were specific to cancer cells with no significant effects observed in normal cells and no adverse effects in treated animals, features not shared by most anticancer drugs. The efficacy of this compound in the absence ...

“…Such modifications can be used for therapeutic purposes, an approach termed ''membrane-lipid therapy'' (7,24). Indeed, lipid molecules such as edelfosine and mitelfosine are potent antineoplastic drugs that target the membrane (25,26), and they induce apoptosis in cancer cells through mechanisms that alter membrane lipid raft organization (26).…”

Section: Discussionmentioning

confidence: 99%

“…In this context, anthracyclines that are unable to enter cancer cells or bind to DNA still have strong antitumor activity (6). Indeed, those used in human therapy regulate plasma membrane structure, and they induce changes in the localization and activity of important peripheral signaling proteins, such as G proteins and PKC (4,7,8). This mode of action also appears to be responsible for the activity of hexamethylene bisacetamide against cancers (9,10).…”

mentioning

confidence: 99%

Pivotal role of dihydrofolate reductase knockdown in the anticancer activity of 2-hydroxyoleic acid

Lladó¹,

Terés

Higuera

et al. 2009

Self Cite

␣-Hydroxy-9-cis-octadecenoic acid, a synthetic fatty acid that modifies the composition and structure of lipid membranes. 2-Hydroxyoleic acid (HOA) generated interest due to its potent, yet nontoxic, anticancer activity. It induces cell cycle arrest in human lung cancer (A549) cells and apoptosis in human leukemia (Jurkat) cells. These two pathways may explain how HOA induces regression of a variety of cancers. We showed that HOA repressed the expression of dihydrofolate reductase (DHFR), the enzyme responsible for tetrahydrofolate (THF) synthesis. Folinic acid, which readily produces THF without the participation of DHFR, reverses the antitumor effects of HOA in A549 and Jurkat cells, as well as the inhibitory influence on cyclin D and cdk2 in A549 cells, and on DNA and PARP degradation in Jurkat cells. This effect was very specific, because either elaidic acid (an analog of HOA) or other lipids, failed to alter A549 or Jurkat cell growth. THF is a cofactor necessary for DNA synthesis. Thus, impairment of DNA synthesis appears to be a common mechanism involved in the different responses elicited by cancer cells following treatment with HOA, namely cell cycle arrest or apoptosis. Compared with other antifolates, such as methotrexate, HOA did not directly inhibit DHFR but rather, it repressed its expression, a mode of action that offers certain therapeutic advantages. These results not only demonstrate the effect of a fatty acid on the expression of DHFR, but also emphasize the potential of HOA to be used as a wide-spectrum drug against cancer.anticancer ͉ DNA ͉ membrane-lipid therapy ͉ neoplasia ͉ nutrigenetics 2 -Hydroxyoleic acid (HOA) is a potent anticancer drug whose molecular mechanism of action is still not fully understood. Although HOA induces cell cycle exit in human lung cancer (A549) cells (1), it induces apoptosis in human leukemia cells (2). The IC 50 of this drug for most cancer cells studied is in the range of 30-150 M, whereas its IC 50 in normal cells is over 5,000 M (2). Thus, this drug does not produce toxicity at therapeutic doses despite acting efficiently in cell and animal models of human cancers (2, 3). Hence, it is important to define the mode of action of this compound and whether common molecular events underlie its therapeutic effects and the regression of different types of cancer.HOA was developed on the basis that the lipid composition and structure of the plasma membrane can be altered by certain antitumor drugs and that these modifications are involved in their action against cancer (4, 5). In this context, anthracyclines that are unable to enter cancer cells or bind to DNA still have strong antitumor activity (6). Indeed, those used in human therapy regulate plasma membrane structure, and they induce changes in the localization and activity of important peripheral signaling proteins, such as G proteins and PKC (4,7,8). This mode of action also appears to be responsible for the activity of hexamethylene bisacetamide against cancers (9, 10).In the search for molecules capable of i...