New Insight on Solute Carrier Family 27 Member 6 (SLC27A6) in Tumoral and Non-Tumoral Breast Cells.

Long-chain fatty acids are the most abundant fatty acids and are essential for various physiological processes. Translocation of long-chain fatty acids across cell membrane is dependent on transport proteins. Solute carrier family 27 member 6 (SLC27A6) is a transport protein which mediates long-chain fatty acid uptake. The bioinformatic analysis revealed that the expression of SLC27A6 in non-tumoral breast tissue was higher than that in tumoral breast cancer in clinic samples. When SLC27A6 expression in non-tumorigenic cell H184B5F5/M10 was repressed, the fatty acids uptake capacity and cell proliferation was inhibited, and cell cycle was delayed. The protein expression of cell cycle regulators including cell division protein kinase 4 (CDK4), CDK6, and cyclin D1 was significantly decreased in SLC27A6-silenced H184B5F5/M10. By contrast, relatively low SLC27A6 expression in tumorigenic breast cancer cell Hs578T when compared to H184B5F5/M10. Repressing SLC27A6 expression did not affect these phenotypes in Hs578T. The interaction network of SLC27A6 was further investigated via STRING database. The function of these SLC27A6-associated proteins mainly involved in lipid biosynthesis, fatty acid metabolic process, and fatty acid transport. In conclusion, this study reveals inverse correlation between SLC27A6 expression and tumoral tissues and provides a new insight into SLC27A6-mediated cell growth and cell cycle regulation in non-tumorigenic breast cells.

Solute Carrier Family 27 Member 4 (SLC27A4) Enhances Cell Growth, Migration, and Invasion in Breast Cancer Cells.

Fatty acid metabolism is important in the regulation of breast cancer progression. Some of the proteins involved in fatty acid transport have been demonstrated to promote the proliferation, migration, and invasion in breast cancer cells. Solute carrier family 27 member 4 (SLC27A4) is a fatty acid transporter protein and is related to very long chain acyl-CoA synthetase activity. In the present study, bioinformatic analysis revealed that relatively high SLC27A4 expression was observed in all subtypes of breast tumor tissues when compared to normal breast tissues. Silencing SLC27A4 expression significantly reduced uptake of free fatty acids in two breast cancer cell lines, Hs578T and MDA-MB-231. Cell growth inhibition was observed in SLC27A4-silenced Hs578T and cell cycle was arrested at G2/M. In addition, the capacity of migration and invasion decreased in both cell lines after knockdown of SLC27A4. The epithelial⁻mesenchymal transition signaling pathway was inhibited because protein expression of Slug, vimentin, α-smooth muscle actin, and other regulators was lower than that in control cells. Taken together, our results confirm that high SLC27A4 is associated with tumor progression in breast cancer cells. It is worth investigating whether SLC27A4 serves a diagnostic marker and therapeutic target in further studies.

Regulatory mechanism of fatty acid­CoA metabolic enzymes under endoplasmic reticulum stress in lung cancer.

The endoplasmic reticulum (ER) is an organelle involved in various physiological processes such as lipid metabolism, protein synthesis and folding, and cellular calcium storage. In a physiological tumor microenvironment, hypoxia, nutrient deprivation, and calcium dysregulation cause accumulation of unfolded and misfolded proteins. Such accumulation induces ER stress and unfolded protein responses (UPRs). Increased UPR signaling pathways are associated with multiple types of cancer. The influence of ER stress on acyl­CoA metabolic enzymes is not well understood. Evaluation of PRECOG and Kaplan­Meier plotter databases in the present study suggested that high expression of acyl­CoA thioesterase (ACOT)7, ACOT11, ACOT13, soluble carrier family 27 member A4 (SLC27A4) and SLC27A5 was associated with poor clinical outcomes. In addition, expression levels of ACOT7, ACOT11, SLC27A4 and SLC27A5 were not altered after induction of ER stress. By contrast, expression of some enzymes was decreased, such as those of long­chain acyl­CoA synthetase (ACSL)3, ACSL4 and SLC27A2. Fatty acid uptake capacity was suppressed in lung cancer cell lines A549 and CL1­0 after thapsigargin treatment but intracellular reactive oxygen species levels were not suppressed. Gene enrichment and regulatory element analysis were performed; the results provided potential targets for further investigation. On the whole, our findings demonstrate the potential regulatory mechanism of high­expression of acyl­CoA metabolic enzymes, the biological effects of decreased enzyme expression levels, possible regulatory elements, and the interaction network involved in responses to ER stress in lung cancer.

Cytotoxic Oxygenated Steroids from the Soft Coral Nephthea erecta.

A new 10-demethylated steroid, nephtheasteroid A (1), a new 19-oxygenated steroid, nephtheasteroid B (2) as well as five known steroids 3-7 were isolated from the organic extract of a Taiwanese soft coral Nephthea erecta. The structure was determined by means of IR, MS, and NMR techniques. Among these metabolites, 1 is rarely found in steroids possessing a 19-norergostane skeleton. In vitro cytotoxicity study using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that compounds 3 and 4 exhibited cytotoxicity against human chronic myelogenous leukemia (K562), human acute lymphoblastic leukemia (Molt-4), human T lymphoblastoid (Sup-T1), and human leukemic monocyte lymphoma (U937), with IC50 of 6.5-14.0 µM.

Via zinc(II) protoporphyrin to the synthesis of poly(ZnPP-MAA-EGDMA) for the imprinting and selective binding of bilirubin.

Poly(zinc protoporphyrin-methacrylic acid-ethyl glycol dimethylacrylate) (poly(ZnPP-MAA-EGDMA)) imprinted with alpha-bilirubin can cause spectroscopic change in wavelength and absorption intensity due to the metal-ion coordination between ZnPP and bilirubin. The fluorescent imprinted polymer was able to selectively bind alpha-bilirubin. The corresponding imprinted polymer monolith was synthesized by using the functional monomer, methacrylic acid and the fluorescent monomer, zinc(II) protoporphyrin. Although the imprinted polymers (MIPs) using methacrylic acid, protoporphyrin, or zinc(II) protoporphyrin alone as the only functional monomer could bind bilirubin, the imprinting effects were all comparably inferior to the imprinted poly(ZnPP-MAA-EGDMA). Therefore, it revealed that via the combined utilization of ZnPP and MAA for the fluorescent and functional effect, the MIPs thus prepared were then able to create the highly selective cavities. The optimal condition for the heated polymerization of the imprinted poly(ZnPP-MAA-EGDMA) was found to be 60 degrees C for 6 h. The imprinting factor of 3.069 could be achieved from the fluorescent imprinted polymer by comparing the binding results obtained from the MIP and the NIP (non-imprinted polymer). The imprinting factor obtained from bilirubin/biliverdin mixture solution was reduced to 2.111 because of the presence of biliverdin. The selectivity toward bilirubin of 2.269 from the bilirubin/biliverdin mixture was obtained. Therefore, to utilize ZnPP for the preparation of the imprinted materials confirmed the selective binding and detection of bilirubin via the fluorescent approach.