Breast cancer is a collection of diseases in which molecular phenotypes can act as both indicators and mediators of therapeutic strategy. Therefore, candidate therapeutics must be assessed in the ...context of multiple cell lines with known molecular phenotypes. Docosahexaenoic acid (DHA) and curcumin (CCM) are dietary compounds known to antagonize breast cancer cell proliferation. We report that these compounds in combination exert a variable antiproliferative effect across multiple breast cell lines, which is synergistic in SK-BR-3 cells and triggers cell signaling events not predicted by the activity of either compound alone.
Dose response curves for CCM and DHA were generated for five breast cell lines. Effects of the DHA+ CCM combination on cell proliferation were evaluated using varying concentrations, at a fixed ratio, of CCM and DHA based on their individual ED₅₀. Detection of synergy was performed using nonlinear regression of a sigmoid dose response model and Combination Index approaches. Cell molecular network responses were investigated through whole genome microarray analysis of transcript level changes. Gene expression results were validated by RT-PCR, and western blot analysis was performed for potential signaling mediators. Cellular curcumin uptake, with and without DHA, was analyzed via flow cytometry and HPLC.
CCM+DHA had an antiproliferative effect in SK-BR-3, MDA-MB-231, MDA-MB-361, MCF7 and MCF10AT cells. The effect was synergistic for SK-BR-3 (ER⁻ PR⁻ Her2⁺) relative to the two compounds individually. A whole genome microarray approach was used to investigate changes in gene expression for the synergistic effects of CCM+DHA in SK-BR-3 cells lines. CCM+DHA triggered transcript-level responses, in disease-relevant functional categories, that were largely non-overlapping with changes caused by CCM or DHA individually. Genes involved in cell cycle arrest, apoptosis, inhibition of metastasis, and cell adhesion were upregulated, whereas genes involved in cancer development and progression, metastasis, and cell cycle progression were downregulated. Cellular pools of PPARγ and phospho-p53 were increased by CCM+DHA relative to either compound alone. DHA enhanced cellular uptake of CCM in SK-BR-3 cells without significantly enhancing CCM uptake in other cell lines.
The combination of DHA and CCM is potentially a dietary supplemental treatment for some breast cancers, likely dependent upon molecular phenotype. DHA enhancement of cellular curcumin uptake is one potential mechanism for observed synergy in SK-BR-3 cells; however, transcriptomic data show that the antiproliferation synergy accompanies many signaling events unique to the combined presence of the two compounds.
The low-shear microgravity environment, modeled by rotating suspension culture bioreactors called high aspect ratio vessels (HARVs), allows investigation in ground-based studies of the effects of ...microgravity on eukaryotic cells and provides insights into the impact of space flight on cellular physiology. We have previously demonstrated that low-shear modeled microgravity (LSMMG) causes significant phenotypic changes of a select group of Saccharomyces cerevisiae genes associated with the establishment of cell polarity, bipolar budding, and cell separation. However, the mechanisms cells utilize to sense and respond to microgravity and the fundamental gene expression changes that occur are largely unknown. In this study, we examined the global transcriptional response of yeast cells grown under LSMMG conditions using DNA microarray analysis in order to determine if exposure to LSMMG results in changes in gene expression.
LSMMG differentially changed the expression of a significant number of genes (1372) when yeast cells were cultured for either five generations or twenty-five generations in HARVs, as compared to cells grown under identical conditions in normal gravity. We identified genes in cell wall integrity signaling pathways containing MAP kinase cascades that may provide clues to novel physiological responses of eukaryotic cells to the external stress of a low-shear modeled microgravity environment. A comparison of the microgravity response to other environmental stress response (ESR) genes showed that 26% of the genes that respond significantly to LSMMG are involved in a general environmental stress response, while 74% of the genes may represent a unique transcriptional response to microgravity. In addition, we found changes in genes involved in budding, cell polarity establishment, and cell separation that validate our hypothesis that phenotypic changes observed in cells grown in microgravity are reflected in genome-wide changes. This study documents a considerable response to yeast cell growth in low-shear modeled microgravity that is evident, at least in part, by changes in gene expression. Notably, we identified genes that are involved in cell signaling pathways that allow cells to detect environmental changes, to respond within the cell, and to change accordingly, as well as genes of unknown function that may have a unique transcriptional response to microgravity. We also uncovered significant changes in the expression of many genes involved in cell polarization and bud formation that correlate well with the phenotypic effects observed in yeast cells when grown under similar conditions. These results are noteworthy as they have implications for human space flight.
Epidemiological studies have linked fish oil consumption to a decreased incidence of cancer. The anticancer effects of fish oil are mostly attributed to its content of omega‐3 fatty acids: ...eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, DHA, because of its unique effect of altering membrane composition, is often regarded as the major omega‐3 fatty acid involved in anticancer activity. Although use of DHA as an anticancer drug to prevent or treat human cancer in clinical settings has not yet been well established, recent studies suggest that DHA can be very effective as an adjuvant with other anticancer agents. In this article, we present studies that show the role of DHA in improving anticancer drug efficacy. Several in vitro and animal studies suggest that combining DHA with other anticancer agents often improves efficacy of anticancer drugs and also reduces therapy‐associated side effects. Incorporation of DHA in cellular membranes improves drug uptake, whereas increased lipid peroxidation is another mechanism for DHA‐mediated enhanced efficacy of anticancer drugs. In addition, several intracellular targets including cyclooxygenase‐2, nuclear factor kappa B, peroxisome proliferator‐activated receptor gamma, mitogen‐activated protein kinase, AKT, and BCL‐2/BAX are found to play an important role in DHA‐mediated additive or synergistic interaction with anticancer drugs. The data suggest that DHA is a safe, natural compound that can greatly improve the anticancer properties of anticancer drugs. Use of DHA with anticancer treatments provides an avenue to therapeutic improvement that involves less risk or side effects for patients and reduced regulatory burden for implementation.
Knowledge of simulated microgravity （SMG）-induced changes in the pathogenicity of microorganisms is important for success of long-term spaceflight. In a previous study using the high aspect ratio ...vessel bioreactor, we showed that the yeast species Saccharomyces cerevisiae underwent a significant phenotypic response when grown in modeled microgravity, which was reflected in the analysis of gene expression profiles. In this study, we establish that Candida albicans responds to SMG in a similar fashion, demonstrating that there is a conserved response among yeast to this environmental stress. We also report that the growth of C. albicans in SMG results in a morphogenic switch that is consistent with enhanced pathogenicity. Specifically, we observed an increase in filamentous forms of the organism and accompanying changes in the expression of two genes associated with the yeasthyphal transition. The morphological response may have significant implications for astronauts＇ safety, as the fungal pathogen may become more virulent during spaceflight.
The objective of this study was to analyse the impact of the gel structure obtained by different heat-induced temperatures on the in vitro gastric digestibility at pH 2. To achieve this, gels were ...prepared from soy protein, pea protein, albumin from chicken egg white and whey protein isolate at varying temperatures (90, 120 and 140 °C) for 30 min. Gels were characterised prior to digestion via microstructure and SDS-PAGE analysis. Subsequently, the gastric digestion process was followed via the protein hydrolysis and HPSEC analysis up to 180 min. Peptides of different sizes (<5 kDa) were gradually formed during the digestion. Our results showed that gels induced at 140 °C were digested faster. The protein source and gelation temperature had great influence on the in vitro gastric protein digestibility.
Multiple myeloma (MM) remains an incurable malignancy indicating a need for continued investigation of novel therapies. Recent studies have highlighted the role of cyclin-dependent kinases (CDK) in ...the pathogenesis of MM. PD0332991 (Palbociclib) is an orally bioavailable, highly selective inhibitor of the CDK4/6-cyclin complex and downstream retinoblastoma protein (Rb) activation pathway that induces cell cycle arrest in the G1 phase.
In this review, the authors summarize the role of the CDK4/6 signaling pathway in MM. They also summarize the development of PD0332991 as a specific inhibitor of CDK4/6, and the reported preclinical and clinical data supporting the potential role of PD0332991 in MM.
While PD0332991 is essentially cytostatic, inducing prolonged G1 arrest, it enhances the cytotoxic effect of other agents effective in MM, including bortezomib and lenalidomide, as confirmed in early phase clinical trials. However, with a plethora of other drugs of different classes being tested in MM, further development of PD0332991 will depend on defining the most efficacious combination with least toxicity. An unexplored opportunity remains the potential protective effect of PD0332991 against lytic bone lesions of MM. The next few years are likely to better define the place of PD0332991 in the treatment of MM.
Abstract Molluscum contagiosum poxvirus (MCV) type 1 and type 2 encode two chemokine-like proteins MC148R1 and MC148R2. It is believed that MC148R proteins function by blocking the inflammatory ...response. However, the mechanism of the proposed biological activities of MC148R proteins and the role of the additional C-terminal cysteines that do not exist in other chemokines are not understood. Here, we demonstrated in two different assay systems that His-tagged MC148R1 displaces the interaction between CXCL12α and CXCR4. The N-terminal cysteines but not the additional C-terminal cysteines modulate this displacement. His-tagged MC148R1 blocked both CXCL12α-mediated and MIP-1α-mediated chemotaxis. In contrast, MC148R2 blocked MIP-1α-mediated but not CXCL12α-mediated chemotaxis. Immunoprecipitation by antibodies to MC148R1 or CXCL12α followed by immunoblotting and detection by antibodies to the other protein demonstrated physical interaction of His-tagged CXCL12α and His-tagged MC148R1. Interaction with chemokines might mask the receptor interaction site resulting in decreased binding and impairment of the biological activities.
► 2,6-Diisopropylphenyl–docosahexaenoamide conjugates (DIP–DHA) inhibits the proliferation of T-cell leukemic cell lines. ► DIP–DHA resulted in increased activation of caspase-3, and caspase-7. ► ...DIP–DHA significantly downregulated CXCR4 surface expression.
We have previously characterized the effects of 2,6-diisopropylphenyl–docosahexaenoamide (DIP–DHA) conjugates and their analogs on the proliferation and progression of breast cancer cell lines. For this study, we investigated the effects of the DIP–DHA conjugate on 2 representative T cell acute lymphoblastic leukemia (T-ALL) cell lines: CEM and Jurkat. Treatment of both cell lines with DIP–DHA resulted in significantly greater inhibition of proliferation and induction of apoptosis than that of parent compounds, 2,6-diisopropylphenol (DIP) or docosahexaenoate (DHA). Treatment of the cells with DIP–DHA resulted in increased activation of caspase-3, and caspase-7. Furthermore, induction of apoptosis in both cell lines was reversed in the presence of a caspase family inhibitor. Treatment with DIP–DHA reduced mitochondrial membrane potential. These observations suggest that the effects are driven by intrinsic apoptotic pathways. DIP–DHA treatment also downregulated surface CXCR4 expression, an important chemokine receptor involved in cancer metastasis that is highly expressed in both CEM and Jurkat cells. In conclusion, our data suggest that the DIP–DHA conjugate exhibits significantly more potent effects on CEM and Jurkat cells than that of DIP or DHA alone. These conjugates have potential use for treatment of patients with T cell acute lymphoblastic leukemia.
PDF
