δ-Tocotrienol sensitizes and re-sensitizes ovarian cancer cells to cisplatin via induction of G1 phase cell cycle arrest and ROS/MAPK-mediated apoptosis

Fabrizio Fontana, Monica Marzagalli, Michela Raimondi, Valentina Zuco, Nadia Zaffaroni, Patrizia Limonta

Cell Prolif . 2021 Sep 14;e13111. doi: 10.1111/cpr.13111. Online ahead of print.

Abstract

Objectives: Among gynaecologic malignancies, ovarian cancer (OC) represents the leading cause of death for women worldwide. Current OC treatment involves cytoreductive surgery followed by platinum-based chemotherapy, which is associated with severe side effects and development of drug resistance. Therefore, new therapeutic strategies are urgently needed. Herein, we evaluated the anti-tumour effects of Vitamin E-derived δ-tocotrienol (δ-TT) in two human OC cell lines, IGROV-1 and SKOV-3 cells.

Materials and methods: MTT and Trypan blue exclusion assays were used to assess δ-TT cytotoxicity, alone or in combination with other molecules. δ-TT effects on cell cycle, apoptosis, ROS generation and MAPK phosphorylation were investigated by flow cytometry, Western blot and immunofluorescence analyses. The synergism between δ-TT and chemotherapy was evaluated by isobologram analysis.

Results: We demonstrated that δ-TT could induce cell cycle block at G1-S phase and mitochondrial apoptosis in OC cell lines. In particular, we found that the proapoptotic activity of δ-TT correlated with mitochondrial ROS production and subsequent JNK and p38 activation. Finally, we observed that the compound was able to synergize with cisplatin, not only enhancing its cytotoxicity in IGROV-1 and SKOV-3 cells but also re-sensitizing IGROV-1/Pt1 cell line to its anti-tumour effects.

Conclusions: δ-TT triggers G1 phase cell cycle arrest and ROS/MAPK-mediated apoptosis in OC cells and sensitizes them to platinum treatment, thus representing an interesting option for novel chemopreventive/therapeutic strategies for OC.

Zeng Li, Shuai Xiang, Cuijiao Wu, Yingzhen Wang, Xisheng Weng

EFORT Open Rev . 2021 Sep 14;6(9):759-770. doi: 10.1302/2058-5241.6.200072. eCollection 2021 Sep.

Abstract

Vitamin E incorporation into highly cross-linked polyethylene (HXLPE) has been introduced to improve wear resistance, and vitamin E incorporated HXLPE (VEPE) has been used in total hip arthroplasty.The aim of this meta-analysis was to investigate the wear properties of VEPE in clinical practice by synthesizing the data provided in randomized clinical trials.The effects on implant stability, functional outcomes and revision rate of VEPE were also compared with those of HXPLE or ultra-high molecular weight polyethylene (UHMWPE).Literature searches were conducted on 1 January 2020 using MEDLINE, EMBASE, Cochrane and ClinicalTrials.gov databases. Randomized controlled trials (RCTs) comparing the aforementioned parameters between VEPE and standard HXPLE/UHMWPE liners were included.Methodological quality and the bias of the included studies were analysed. Meta-analyses were performed using the Review Manager software.Nine RCTs met the eligibility criteria and were included. At early and mid-term follow-up, the vertical penetration and the total penetration of the femoral head were both significantly reduced in the VEPE group. The steady state wear rate of the VEPE group was also remarkably lower.However, at two-year follow-up, significantly increased cup migration was observed in the VEPE group. Moreover, the mid-term clinical outcomes of the VEPE group were worse, while the total revision rates between the two groups were not significantly different.The limited number of included studies may compromise our conclusion regarding clinical outcomes of the VEPE bearing surface. More RCTs with longer follow-up periods are needed to further investigate the effects of VEPE in total hip arthroplasty.

Sooji Song, Yoon-Mi Lee, Yu Young Lee, Kyung-Jin Yeum

Molecules . 2021 Sep 13;26(18):5564. doi: 10.3390/molecules26185564.

Abstract

Oat (Avena sativa) is well known for its various health benefits. The protective effect of oat extract against oxidative stress-induced apoptosis in human keratinocytes HaCaT was determined. First, extracts of two varieties of oat, Daeyang and Choyang, were analyzed for fat-soluble antioxidants such as α-tocotrienol, γ-oryzanols, lutein and zeaxanthin using an UPLC system and for antioxidant activity using a DPPH assay. Specifically, an 80% ethanol extract of Daeyang oat (Avena sativa cv. Daeyang), which had high amounts of antioxidants and potent radical scavenging activity, was further evaluated for protective effect against oxidative stress-induced cell death, intracellular reactive oxygen species levels, the phosphorylation of DNA damage mediating genes such as H2AX, checkpoint kinase 1 and 2, and p53 and the activation of apoptotic genes such as cleaved caspase-3 and 7 and poly (ADP-ribose) polymerase in HaCaT cells. The Daeyang and Choyang oat 80% ethanol extracts had 26.9 and 24.1 mg/100 g γ-oryzanols, 7.69 and 8.38 mg/100 g α-tocotrienol, 1.25 and 0.34 mg/100 g of lutein and 1.20 and 0.17 mg/100 g of zeaxanthin, respectively. The oat 80% ethanol extract treatment (Avena sativa cv. Daeyang) had a protective effect on oxidative stress-induced cell death in HaCaT cells. In addition, the oat 80% ethanol extracts led to a significant decrease in the intracellular ROS level at a concentration of 50-200 μg/mL, the attenuation of DNA damage mediating genes and the inhibition of apoptotic caspase activities in a dose dependent manner (50-200 μg/mL). Thus, the current study indicates that an oat (Avena sativa cv. Daeyang) extract rich in antioxidants, such as polyphenols, avenanthramides, γ-oryzanols, tocotrienols and carotenoids, has a protective role against oxidative stress-induced keratinocyte injuries and that oat may a useful source for oxidative stress-associated skin damage.

Raluca P Dumitriu, Elena Stoleru, Geoffrey R Mitchell, Cornelia Vasile, Mihai Brebu

Molecules . 2021 Sep 10;26(18):5498. doi: 10.3390/molecules26185498.

Abstract

Antioxidant activity is an important feature for food contact materials such as packaging, aiming to preserve freshness and retard food spoilage. Common bioactive agents are highly susceptible to various forms of degradation; therefore, protection is required to maintain functionality and bioavailability. Poly(ε-caprolactone) (PCL), a biodegradable GRAS labeled polymer, was used in this study for encapsulation of α-tocopherol antioxidant, a major component of vitamin E, in the form of electrospun fibers. Rheological properties of the fiber forming solutions, which determine the electrospinning behavior, were correlated with the properties of electrospun fibers, e.g., morphology and surface properties. Interactions through hydrogen bonds were evidenced between the two components. These have strong effect on structuration of macromolecular chains, especially at low α-tocopherol amounts, decreasing viscosity and elastic modulus. Intra-molecular interactions in PCL strengthen at high α-tocopherol amounts due to decreased solvation, allowing good structural recovery after cease of mechanical stress. Morphologically homogeneous electrospun fibers were obtained, with ~6 μm average diameter. The obtained fibers were highly hydrophobic, with fast release in 95% ethanol as alternative simulant for fatty foods. This induced good in vitro antioxidant activity and significant in vivo reduction of microbial growth on cheese, as determined by respirometry. Therefore, the electrospun fibers from PCL entrapping α-tocopherol as bioactive agent showed potential use in food packaging materials.

Nor Faeizah Ibrahim, Hamizah Shahirah Hamezah, Daijiro Yanagisawa, Mayumi Tsuji, Yuji Kiuchi, Kenjiro Ono, Ikuo Tooyama

Biochem Biophys Rep . 2021 Sep 10;28:101131. doi: 10.1016/j.bbrep.2021.101131. eCollection 2021 Dec.

Abstract

One of the neuropathological hallmarks of Alzheimer’s disease (AD)-causing neurodegeneration and consequent memory deterioration, and eventually, cognitive decline-is amyloid-β (Aβ) aggregation forming amyloid plaques. Our previous study showed the potential of a tocotrienol-rich fraction-a mixture of naturally occurring of vitamin E analogs-to inhibit Aβ aggregation and restore cognitive function in an AD mouse model. The current study examined the effect of three vitamin E analogs-α-tocopherol (α-TOC), α-tocotrienol (α-T3), and γ-tocotrienol (γ-T3)-on Aβ aggregation, disaggregation, and oligomerization in vitro. Thioflavin T (ThT) assay showed α-T3 reduced Aβ aggregation at 10 μM concentration. Furthermore, both α-T3 and γ-T3 demonstrated Aβ disaggregation, as shown by the reduction of ThT fluorescence. However, α-TOC showed no significant effect. We confirmed the results for ThT assays with scanning electron microscopy imaging. Further investigation in photo-induced cross-linking of unmodified protein assay indicated a reduction in Aβ oligomerization by γ-T3. The present study thus revealed the individual effect of each tocotrienol analog in reducing Aβ aggregation and oligomerization as well as disaggregating preformed fibrils.

Nur-Vaizura Mohamad, Soelaiman Ima-Nirwana, Kok-Yong Chin

Int J Med Sci . 2021 Sep 9;18(16):3665-3673. doi: 10.7150/ijms.64045. eCollection 2021.

Abstract

Menopause is the leading cause of osteoporosis for elderly women due to imbalanced bone remodelling in the absence of oestrogen. The ability of tocotrienol in reversing established bone loss due to oestrogen deficiency remains unclear despite the plenitude of evidence showcasing its preventive effects. This study aimed to investigate the effects of self-emulsified annatto tocotrienol (SEAT) on bone histomorphometry and remodelling in ovariectomised rats. Female Sprague Dawley rats (n=36) were randomly assigned into baseline, sham, ovariectomised (OVX) control, OVX-treated with annatto tocotrienol (AT) (60 mg/kg), SEAT (60 mg/kg) and raloxifene (1 mg/kg). Daily treatment given through oral gavage was started two months after castration. The rats were euthanised after eight weeks of treatment. Blood was collected for bone biomarkers. Femur and lumbar bones were collected for histomorphometry and remodelling markers. The results showed that AT and SEAT improved osteoblast numbers and trabecular mineralisation rate (p<0.05 vs untreated OVX). AT also decreased skeletal sclerostin expression in OVX rats (p<0.05 vs untreated OVX). Similar effects were observed in the raloxifene-treated group. Only SEAT significantly increased bone formation rate and reduced RANKL/OPG ratio (p<0.05 vs untreated OVX). However, no changes in osteoclast-related parameters were observed among the groups (p>0.05). In conclusion, SEAT exerts potential skeletal anabolic properties by increasing bone formation, suppressing sclerostin expression and reducing RANKL/OPG ratio in rats with oestrogen deficiency.

Lan Li, Rujun Jin, Ying Li, Hee Su Yoon, Hyeon Jeong Yoon, Kyung Chul Yoon

Cutan Ocul Toxicol . 2021 Sep 8;1-9. doi: 10.1080/15569527.2021.1973022. Online ahead of print.

Abstract

Purpose: To investigate the efficacy of topical application of 3% diquafosol sodium (DQS) and tocopherol (TCP) acetate mixtures in a mouse model of experimental dry eye (EDE).

Methods: After exposure to desiccating stress for 5 days, eye drops consisting of 3% DQS alone, 0.01% TCP alone, or 3% DQS and 0.005% or 0.01% TCP mixture were applied for the treatment of EDE. Tear volume, tear film break-up time (TBUT), corneal fluorescein staining scores (CFSS), and tear film lipid layer grades (TFLLG) were measured at 0, 5 and 10 days after treatment. The 2′,7′-dichlorodihydrofluorescein diacetate assay (DCFDA) for reactive oxygen species (ROS) production, enzyme-linked immunosorbent assay (ELISA) for malondialdehyde (MDA), and flow cytometry for CD4 + interferon (IFN)-γ+ T cells were evaluated on the ocular surface at 10 days after treatment. In addition, levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and chemokine CC motif ligand 4 (CCL4) in the conjunctiva were measured using a multiplex immunobead assay, and conjunctival goblet cells were counted by periodic acid-Schiff staining at 10 days after treatment.

Results: Both the TCP mixture groups indicated a significant improvement in TBUT, ROS production, and MDA concentrations compared to those in the DQS alone group. Furthermore, the 0.01% TCP mixture group also showed higher tear film lipid layer grades and conjunctival goblet cell density and lower corneal fluorescein staining scores, number of CD4 + IFN-γ+ T cells, and levels of TNF-α, IL-1β, and CCL4 than the DQS alone group (P < 0.05).

Conclusions: Application of eye drops containing the mixture of DQS and TCP could stabilize the tear film lipid layer, improve TBUT and corneal epithelial damages, decrease ROS production, inflammatory molecules, and T cells, and increase conjunctival goblet cell density on the ocular surface. Topical DQS and TCP mixtures may have a greater therapeutic effect on clinical signs, oxidative damage, and inflammation of dry eye than DQS eye drops.

Shigesaburo Ogawa, Haruka Katsuragi, Katsuya Iuchi, Setsuko Hara

J Oleo Sci . 2021 Sep 8. doi: 10.5650/jos.ess21064. Online ahead of print.

Abstract

The precise understanding of the behaviour of vitamin E (α-tocopherol; Toc) complexed with cyclodextrin (CD) additives in aqueous solution is a fundamental issue for further development of their aqua-related biological applications. In this study, the solubilisation and complexation behaviours of Toc with methyl-substituted CD derivatives and the radical scavenging ability of the resulting complexes were precisely investigated in water media. Several problems were encountered upon pre-dissolving Toc in an organic solvent prior to the addition to the water media, such as enhancement of the dispersibility and decrease in the complexation capacity. Additionally, dispersions were obtained in some cases when mixing CD and Toc even in the absence of an organic solvent; therefore, to perform the measurements, a transparent solution was prepared via filtration with a nanopore filter. Consequently, unexpectedly, the addition of certain CD methylated derivatives did not always enhance the solubility of Toc significantly. However, 2,6-di-O-methylated β-CD (2,6-DMCD) formed a water-soluble inclusion complex with Toc, effectively enhancing its solubility. A phase solubility study indicated the formation of 1:2 or 1:3 Toc/CD inclusion complexes, and the interaction of 2,6-DMCD with both the chromanol head and the phytol chain of Toc was revealed by 2D ROESY nuclear magnetic resonance analysis. The interaction between 2,6-DMCD and the chromanol head was also confirmed for a 2,6-DMCD-2,2,5,7,8-pentamethyl-6-chromanol inclusion complex. Additionally, a rapid scavenging effect for molecularly dissolved Toc was demonstrated even in a system comprising a chromanol head directly encapsulated by CD. Hence, this work elucidated the precise complexation and radical scavenging ability of 2,6-DMCD-Toc in an aqueous solution, which paves the way for its biological applications.

Etsuo Niki

Free Radic Biol Med . 2021 Sep 3;176:1-15. doi: 10.1016/j.freeradbiomed.2021.09.001. Online ahead of print.

Abstract

Lipids are oxidized in vivo by multiple oxidizing species with different properties, some by regulated manner to produce physiological mediators, while others by random mechanisms to give detrimental products. Vitamin E plays an important role as a physiologically essential antioxidant to inhibit unregulated lipid peroxidation by scavenging lipid peroxyl radicals to break chain propagation independent of the type of free radicals which induce chain initiation. Kinetic data suggest that vitamin E does not act as an efficient scavenger of nitrogen dioxide radical, carbonate anion radical, and hypochlorite. The analysis of regio- and stereo-isomer distribution of the lipid oxidation products shows that, apart from lipid oxidation by CYP enzymes, the free radical-mediated lipid peroxidation is the major pathway of lipid oxidation taking place in humans. Compared with healthy subjects, the levels of racemic and trans,trans-hydro (pero)xyoctadecadienoates, specific biomarker of free radical lipid oxidation, are elevated in the plasma of patients including atherosclerosis and non-alcoholic fatty liver diseases. α-Tocopherol acts as a major antioxidant, while γ-tocopherol scavenges nitrogen dioxide radical, which induces lipid peroxidation, nitration of aromatic compounds and unsaturated fatty acids, and isomerization of cis-fatty acids to trans-fatty acids. It is essential to appreciate that the antioxidant effects of vitamin E depend on the nature of both oxidants and substrates being oxidized. Vitamin E, together with other antioxidants such as vitamin C, contributes to the inhibition of detrimental oxidation of biological molecules and thereby to the maintenance of human health and prevention of diseases.

Yi Xiao, Edward Ki Yun Leung

Am J Clin Pathol . 2021 Aug 31;aqab088. doi: 10.1093/ajcp/aqab088. Online ahead of print.

Abstract

Objectives: Fat-soluble vitamins are measured to identify deficiencies that may lead to rickets, osteomalacia, night blindness, and reversible motor and sensory neuropathies. We present a rapid liquid chromatography-mass spectrometry (LC-MS/MS) method that simultaneously measures 25-hydroxyvitamin D3 (25[OH]D3), epi-25(OH)D3, 25(OH)D2, vitamin A, α-tocopherol, and γ-tocopherol.

Methods: We mixed 100 µL serum with internal standard and extracted it by using supported liquid extraction plates. Reconstituted specimens were analyzed by LC-MS/MS with a 10-minute gradient.

Results: The method was linear, covering physiological levels with r2 > 0.99, and the total precision was less than 15% at all quality control levels. The lower limit of the measuring intervals for 25(OH)D3, epi-25(OH)D3, 25(OH)D2, vitamin A, α-tocopherol, and γ-tocopherol were 4 ng/mL, 4 ng/mL, 4 ng/mL, 1 µg/dL, 0.2 µg/mL, and 0.2 µg/mL, respectively, with coefficient of variation of 20% or less. Recoveries were between 92% and 111% for National Institute of Standards and Technology reference materials and 81% and 122% for spike-recovery studies. Comparison studies for vitamin D total, vitamin A, and α-tocopherol demonstrated slopes between 1.04 and 1.11 and r2 between 0.94 and 0.96. Minimal matrix effect was observed for all analytes.

Conclusions: We developed and validated a rapid LC-MS/MS method for the simultaneous measurement of 25(OH)D3, epi-25(OH)D3, 25(OH)D2, vitamin A, α-tocopherol, and γ-tocopherol.