Exploiting the Metabolic Consequences of PTEN Loss and Akt/Hexokinase 2 Hyperactivation in Prostate Cancer: A New Role for δ-Tocotrienol

Fabrizio Fontana, Martina Anselmi, Patrizia Limonta

Int J Mol Sci . 2022 May 9;23(9):5269. doi: 10.3390/ijms23095269.

Abstract

The Warburg effect is commonly recognized as a hallmark of nearly all tumors. In prostate cancer (PCa), it has been shown to be driven by PTEN loss- and Akt hyperactivation-associated upregulation of hexokinase 2 (HK2). δ-Tocotrienol (δ-TT) is an extensively studied antitumor compound; however, its role in affecting PCa glycolysis is still unclear. Herein, we demonstrated that δ-TT inhibits glucose uptake and lactate production in PTEN-deficient LNCaP and PC3 PCa cells, by specifically decreasing HK2 expression. Notably, this was accompanied by the inhibition of the Akt pathway. Moreover, the nutraceutical could synergize with the well-known hypoglycemic agent metformin in inducing PCa cell death, highlighting the crucial role of the above metabolic phenotype in δ-TT-mediated cytotoxicity. Collectively, these results unravel novel inhibitory effects of δ-TT on glycolytic reprogramming in PCa, thus providing new perspectives into the mechanisms of its antitumor activity and into its use in combination therapy.

Anna Maria Rychter, Szymon Hryhorowicz, Ryszard Słomski, Agnieszka Dobrowolska, Iwona Krela-Kaźmierczak

Clin Nutr . 2022 May 6;41(7):1557-1565. doi: 10.1016/j.clnu.2022.04.032. Online ahead of print.

Abstract

Proper dietary habits are a vital element of cardiovascular (CV) treatment, and – according to the current guidelines – a diet rich in antioxidants is generally recommended. It remains, however, inconclusive whether antioxidant nutrients should be supplemented for CV health, and if so, in which form and dosage. Currently available data suggest that vitamin E may be essential in preventing CVD, especially in coronary heart disease and atherosclerosis – nevertheless, vitamin E supplementation may be questionable and may even be associated with adverse outcomes. Further, current studies highlight a strong need for identifying sex-specific strategies, which could improve guidelines for both the prevention and management of cardiovascular disease (CVD). It should also be emphasized that understanding the role of genetic variants in genes involved in VE metabolism may also be crucial for more precise nutritional recommendations for patients suffering from CVD. Therefore, we summarize the current knowledge regarding vitamin E antioxidant properties, which could be essential from CV perspective, and aim to assess whether vitamin E supplementation can be beneficial in CV prevention, especially in the high-risk group of women with obesity.

Aslina Pahrudin Arrozi, Siti Nur Syazwani Shukri, Nuraqila Mohd Murshid, Ahmad Baihaqi Ahmad Shahzalli, Wan Zurinah Wan Ngah, Hanafi Ahmad Damanhuri, Suzana Makpol

Front Cell Neurosci . 2022 May 5;16:846459. doi: 10.3389/fncel.2022.846459. eCollection 2022.

Abstract

The amyloid precursor protein (APP) processing pathway was altered in Alzheimer’s disease (AD) and contributed to abnormal amyloid-beta (Aβ) production, which forms insoluble interneuron protein aggregates known as amyloid plaques in the brain. Targeting the APP processing pathway is still fundamental for AD modifying therapy. Extensive research has evaluated the protective effects of vitamin E as an antioxidant and as a signaling molecule. The present study aimed to investigate the modulatory effects of different tocopherol isomers on the expression of genes involved in regulating the APP processing pathway in vitro. The screening for the effective tocopherol isomers in reducing APP expression and Aβ-42 was carried out in SH-SY5Y stably overexpressed APP Swedish. Subsequently, quantitative one-step real-time PCR was performed to determine the modulatory effects of selected tocopherol isomers on the expression of genes in SH-SY5Y stably overexpressed three different types of APP (wild-type, APP Swedish, and APP Swedish/Indiana). Our results showed that all tocopherol isomers, especially at higher concentrations (80-100 μM), significantly increased (p < 0.05) the cell viability in all cells group, but only α-tocopherol (ATF) and γ-tocopherol (GTF) significantly decreased (p < 0.05) the APP mRNA level without statistically significant APP protein level, accompanied with a reduced significance (p < 0.05) on the level of Aβ-42 in SH-SY5Y APP Swedish. On the other hand, β- and δ-tocopherol (BTF and DTF) showed no effects on the level of APP expression and Aβ-42. Subsequent results demonstrated that ATF and GTF significantly decreased (p < 0.05) the expression of gene beta-site APP cleaving enzyme (BACE1), APH1B, and Nicastrin (NCSTN), but significantly increased (p < 0.05) the expression of Sirtuin 1 (SIRT1) in SH-SY5Y stably expressed the mutant APP form. These findings suggested that ATF and GTF could modulate altered pathways and may help ameliorate the burden of amyloid load in AD.

Genea Edwards, Caroline G Olson, Carlyn P Euritt, Peter Koulen

Front Neurosci . 2022 May 4;16:890021. doi: 10.3389/fnins.2022.890021. eCollection 2022.

Abstract

The eye is particularly susceptible to oxidative stress and disruption of the delicate balance between oxygen-derived free radicals and antioxidants leading to many degenerative diseases. Attention has been called to all isoforms of vitamin E, with α-tocopherol being the most common form. Though similar in structure, each is diverse in antioxidant activity. Preclinical reports highlight vitamin E’s influence on cell physiology and survival through several signaling pathways by activating kinases and transcription factors relevant for uptake, transport, metabolism, and cellular action to promote neuroprotective effects. In the clinical setting, population-based studies on vitamin E supplementation have been inconsistent at times and follow-up studies are needed. Nonetheless, vitamin E’s health benefits outweigh the controversies. The goal of this review is to recognize the importance of vitamin E’s role in guarding against gradual central vision loss observed in age-related macular degeneration (AMD). The therapeutic role and molecular mechanisms of vitamin E’s function in the retina, clinical implications, and possible toxicity are collectively described in the present review.

Amira Ebrahim Alsemeh, Marwa Mahmood Ahmed, Amal Fawzy, Walaa Samy, Marwa Tharwat, Samar Rezq

Life Sci . 2022 May 1;296:120434. doi: 10.1016/j.lfs.2022.120434. Epub 2022 Feb 25.

Abstract

Aims: Valproic acid (VPA), a commonly used antiepileptic drug, can induce testicular oxidative stress and injury. Altered autophagic response usually follows testicular injury. The study aims to evaluate the role of autophagy in the protective effect of the antioxidant vitamin E (Vit E) against VPA-induced testicular injury.

Materials and methods: VPA (100, 300, and 500 mg/kg/day) was administered for 8 days. The protective group received both Vit E (50 mg/kg) and VPA (500 mg/kg). The testicular weight, sperm analysis, and serum testosterone concentration, as well as testicular histopathology, steroidogenic gene expression, and oxidative stress markers were evaluated. The mRNA or protein expression of autophagy-related proteins [adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), microtubule-associated protein light chain 3 (LC3), Beclin1, and p62] were measured using RT-PCR or immunohistochemistry.

Key findings: VPA resulted in lower testes weight and sperm quality with aberrant morphology. VPA dose-dependently induced testicular oxidative stress, which was associated with decreased steroidogenic gene expression and serum testosterone levels, as well as deteriorated histopathology. These biochemical and histological changes were also associated with autophagy induction (higher LC3 and Beclin1, and lower p62) that was lost with the highest toxic dose (500 mg/kg). The attenuated autophagy with the highest dose was accompanied by AMPK downregulation and mTOR upregulation. Vit E protected against VPA-mediated oxidative stress and toxicity while also restoring autophagic response and AMPK/mTOR levels.

Haiyang Kou, Zhong Qing, Hao Guo, Rui Zhang, Jianbing Ma

Eur J Clin Nutr . 2022 Apr 25. doi: 10.1038/s41430-022-01148-9. Online ahead of print.

Abstract

Objective: The purpose of this study was to evaluate the safety and effectiveness of vitamin E in rheumatoid arthritis patients.

Methods: A computerized search of PubMed, Embase, The Cochrane Library, and Web of Science databases was conducted to find published randomized controlled trials of vitamin E in rheumatoid arthritis; the experimental group was treated with vitamin E, while the control group was treated with placebo, other drugs, or external therapy; the search period was from the time each database was established to December 31, 2021, and a meta-analysis was conducted using Rev Man 5.4 software.

Results: This research eventually comprised nine publications with a total of 39,845 patients. Vitamin E supplementation was shown to be more effective in individuals with RA for sensitive joints (MD = -1.66, 95% CI – -6.32-2.99; I² = 93%; P < 0.00001) and swollen joints (MD = -0.46, 95% CI – -1.98-1.07; I² = 56%; P = 0.08).

Conclusions: Vitamin E’s ability to restore the intestinal barrier and improve the gastrointestinal tract may be linked to the prevention and treatment of rheumatoid arthritis. Vitamin E supplements used on a regular basis can help individuals with RA reduce joint discomfort, edema, and stiffness, as well as enhance their overall quality of life.

Sarita Garg, Tarun K Garg, Stephen Y Wise, Oluseyi O Fatanmi, Isabelle R Miousse, Alena V Savenka, Alexei G Basnakian, Vijay K Singh, Martin Hauer-Jensen

Int J Mol Sci . 2022 Apr 22;23(9):4643. doi: 10.3390/ijms23094643.

Abstract

The gastrointestinal (GI) system is highly susceptible to irradiation. Currently, there is no Food and Drug Administration (FDA)-approved medical countermeasures for GI radiation injury. The vitamin E analog gamma-tocotrienol (GT3) is a promising radioprotector in mice and nonhuman primates (NHP). We evaluated GT3-mediated GI recovery in total-body irradiated (TBI) NHPs. Sixteen rhesus macaques were divided into two groups; eight received vehicle and eight GT3 24 h prior to 12 Gy TBI. Proximal jejunum was assessed for structural injuries and crypt survival on day 4 and 7. Apoptotic cell death and crypt cell proliferation were assessed with TUNEL and Ki-67 immunostaining. Irradiation induced significant shortening of the villi and reduced mucosal surface area. GT3 induced an increase in crypt depth at day 7, suggesting that more stem cells survived and proliferated after irradiation. GT3 did not influence crypt survival after irradiation. GT3 treatment caused a significant decline in TUNEL-positive cells at both day 4 (p < 0.03) and 7 (p < 0.0003). Importantly, GT3 induced a significant increase in Ki-67-positive cells at day 7 (p < 0.05). These data suggest that GT3 has radioprotective function in intestinal epithelial and crypt cells. GT3 should be further explored as a prophylactic medical countermeasure for radiation-induced GI injury.

Xiangliang Yuan, Yimin Duan, Yi Xiao, Kai Sun, Yutao Qi, Yuan Zhang, Zamal Ahmed, Davide Moiani, Jun Yao, Hongzhong Li, Lin Zhang, Arseniy E Yuzhalin, Ping Li, Chenyu Zhang, Akosua Badu-Nkansah, Yohei Saito, Xianghua Liu, Wen-Ling Kuo, Haoqiang Ying, Shao-Cong Sun, Jenny C Chang, John A Tainer, Dihua Yu

Cancer Discov . 2022 Apr 14;candisc.0900.2021. doi: 10.1158/2159-8290.CD-21-0900. Online ahead of print.

Abstract

Despite the popular use of dietary supplements during conventional cancer treatments, their impacts on the efficacies of prevalent immunotherapies, including immune checkpoint therapy (ICT), are unknown. Surprisingly, our analyses of electronic health records revealed that ICT-treated cancer patients who took vitamin E (VitE) had significantly improved survival. In mouse models, VitE increased ICT antitumor efficacy, which depended on dendritic cells (DCs). VitE entered DCs via SCARB1 receptor and restored tumor-associated DCs’ functionality by directly binding to and inhibiting protein tyrosine phosphatase SHP1, a DC-intrinsic checkpoint. SHP1 inhibition, genetically, or by VitE treatment, enhanced tumor antigen cross-presentation by DCs and DC-derived extracellular vesicles (DC-EVs) triggering systemic antigen-specific T cell antitumor immunity. Combining VitE with DC-recruiting cancer vaccines, or immunogenic chemotherapies, greatly boosted ICT efficacy in animals. Therefore, combining VitE supplement, or SHP1-inhibited DCs/DC-EVs, with DCs-enrichment therapies could substantially augment T cell antitumor immunity and enhance the efficacies of cancer immunotherapies.

Myunghee Kim, Hyeyoon Eo, Josephine Gahyun Lim, Hyunjung Lim, Yunsook Lim

Nutrients . 2022 Apr 12;14(8):1599. doi: 10.3390/nu14081599.

Abstract

Vitamin E plays an important role in attenuating muscle damage caused by oxidative stress and inflammation. Despites of beneficial effects from antioxidant supplementation, effects of antioxidants on exercise-induced muscle damage are still unclear. The aim of this meta-analysis was to investigate the effects of dietary vitamin E supplementation on exercise-induced muscle damage, oxidative stress, and inflammation in randomized controlled trials (RCTs). The literature search was conducted through PubMed, Medline, Science Direct, Scopus, SPORTDiscuss, EBSCO, Google Scholar database up to February 2022. A total of 44 RCTs were selected, quality was assessed according to the Cochrane collaboration risk of bias tool (CCRBT), and they were analyzed by Revman 5.3. Dietary vitamin E supplementation had a protective effect on muscle damage represented by creatine kinase (CK; SMD -1.00, 95% CI: -1.95, -0.06) and lactate dehydrogenase (SMD -1.80, 95% CI: -3.21, -0.39). Muscle damage was more reduced when CK was measured immediately after exercise (SMD -1.89, 95% CI: -3.39, -0.39) and subjects were athletes (SMD -5.15, 95% CI: -9.92, -0.39). Especially vitamin E supplementation lower than 500 IU had more beneficial effects on exercise-induced muscle damage as measured by CK (SMD -1.94, 95% CI: -2.99, -0.89). In conclusion, dietary vitamin E supplementation lower than 500 IU could prevent exercise-induced muscle damage and had greater impact on athletes.

Ghazale Tefagh, Moloud Payab, Mostafa Qorbani, Farshad Sharifi, Yasaman Sharifi, Mahbubeh Sadat Ebrahimnegad Shirvani, Farzad Pourghazi, Rasha Atlasi, Zhaleh Shadman, Nafiseh Rezaei, Erfan Mohammadi-Vajari, Bagher Larijani, Mahbube Ebrahimpur

Sci Rep . 2022 Apr 6;12(1):5770. doi: 10.1038/s41598-022-09082-3.

Abstract

Polycystic ovary syndrome (PCOS) is a common endocrinopathy among reproductive-age women. Various therapeutical approaches are currently used to manage or control symptoms associated with PCOS. This systematic review intended to assess the effects of Vit E supplementation on cardiometabolic risk factors, inflammatory and oxidative markers, and hormonal functions in PCOS women based on the clinical trial’s results. The databases including PubMed, Scopus, Cochrane, Web of Science, and Embase were used to find all relevant studies. The authors reviewed all relevant clinical trials via systematic evaluation of abstracts and titles. Searches were conducted on August 1, 2020. After the initial search and reading of the article’s title and abstract, 353 articles were reviewed; finally, 12 articles met the inclusion criteria. Vitamin E supplementation improves lipid profile, decreases insulin and HOMA-IR levels. Furthermore, while Vitamin E supplementation decreases LH and testosterone concentrations, it increases FSH and progestrone concentrations. The following meta-analysis showed that vitamin E supplementation made statistically significant improvements in triglyceride (TG) and low-density lipoproteins (LDL) levels, meanwhile, pooled mean difference for waist circumference (WC) and HOMA-IR were also statistically significant. Supplementary regimens containing vitamin E can positively affect metabolic and hormonal parameters in women with PCOS.