Gamma-Tocotrienol loaded liposomes as radioprotection from hematopoietic side effects caused by radiotherapeutic drugs

Sang-Gyu Lee, Teja Muralidhar Kalidindi, Hanzhi Lou, Kishore Gangangari, Blesida Punzalan, Ariana Bitton 2, Casey Lee, Soobin Park, Lisa Bodei, Michael Kharas, Vijay K Singh, NagaVaraKishore Pillarsetty, Steven M Larson

J Nucl Med . 2020 Aug 21;jnumed.120.244681. doi: 10.2967/jnumed.120.244681. Online ahead of print.


Rationale: With the successful development and increased use of targeted radionuclide therapy for treating cancer comes the increased risk of radiation injury to bone marrow-both direct suppression and stochastic effects, leading to neoplasia. Herein, we report a novel radioprotector drug, a liposomal formulation of gamma-tocotrienol (GT3), or GT3-Nano for short, to mitigate bone marrow radiation damage during targeted radionuclide therapy (TRT). Methods: GT3 was loaded into liposomes using passive loading. [64Cu]-GT3-Nano and 3H-GT3-Nano were synthesized to study the in vivo biodistribution profile of the liposome and GT3 individually. Radioprotection efficacy of GT3-Nano was assessed after acute 137Cs whole-body irradiation at sublethal (4 Gy), lethal (9 Gy), or single high-dose [153Sm]-EDTMP administration. Flow cytometry was used to analyze hematopoietic cell population dynamics and fluorescence microscopy was used to assess the cellular site of GT3-Nano localization in the spleen and bone marrow. Results: Bone marrow uptake and retention of [64Cu]-GT3-Nano was 6.98 ± 2.34 %ID/g, while [3H]-GT3-Nano uptake and retention was 7.44 ± 2.52 %ID/g at 24 h, respectively. GT3-Nano administered 24 hours before or after 4 Gy TBI promoted rapid and complete hematopoietic recovery while recovery of controls stalled at 60%. GT3-Nano demonstrated dose-dependent radioprotection, achieving 90% survival at 50 mg/kg against lethal 9 Gy TBI. Flow cytometry of bone marrow indicated progenitor bone marrow cells MPP2 and CMP cells were upregulated in GT3-Nano-treated mice. Immunohistochemistry showed that GT3-Nano accumulates in CD105-positive sinusoid epithelial cells. Conclusion: GT3-Nano is highly effective in mitigating marrow suppressive effects of sub-lethal and lethal TBI in mice. GT3-Nano can aid in rapid recovery of hematopoietic components in mice treated with the endoradiotherapeutic agent [153Sm]-EDTMP.

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Synergistic Impact of Xanthorrhizol and d-δ-Tocotrienol on the Proliferation of Murine B16 Melanoma Cells and Human DU145 Prostate Carcinoma Cells

Darren Chan, Maureen L Meister, Chappell R Madhani, Manal Elfakhani, Sophie T Yount, Xiangming Ji, Rafaela G Feresin, Desiree Wanders, Huanbiao Mo

Nutr Cancer . 2020 Aug 18;1-12. doi: 10.1080/01635581.2020.1807573. Online ahead of print


Isoprenoids suppress the mevalonate pathway that provides prenyl groups for the posttranslational modification of growth-regulating proteins. We hypothesize that xanthorrhizol and d-δ-tocotrienol synergistically suppress the growth of murine B16 melanoma and human DU145 prostate carcinoma cells. Xanthorrhizol (0-200 µmol/L; half maximal inhibitory concentration [IC50] = 65 µmol/L) and d-δ-tocotrienol (0-40 µmol/L; IC50 = 20 µmol/L) each induced a concentration-dependent suppression of the proliferation of B16 cells and concurrent cell cycle arrest at the G1 phase. A blend of 16.25 µmol/L xanthorrhizol and 10 µmol/L d-δ-tocotrienol suppressed B16 cell proliferation by 69%, an impact greater than the sum of those induced by xanthorrhizol (15%) and d-δ-tocotrienol (12%) individually. The blend cumulatively reduced the levels of cyclin-dependent kinase four and cyclin D1, key regulators of cell cycle progression at the G1 phase. The expression of RAS and extracellular signal-regulated kinase (ERK1/2) in the proliferation-stimulating RAS-RAF-MEK-ERK pathway was downregulated by the blend. Xanthorrhizol also induced a concentration-dependent suppression of the proliferation of DU145 cells with concomitant morphological changes. Isobologram confirmed the synergistic effect of xanthorrhizol and d-δ-tocotrienol on DU145 cell proliferation with combination index values ranging 0.61-0.94. Novel combinations of isoprenoids with synergistic actions may offer effective approaches in cancer prevention and therapy.

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Primary and Secondary Markers of Doxorubicin-Induced Female Infertility and the Alleviative Properties of Quercetin and Vitamin E in a Rat Model

Mohammad Samare-Najaf, Fatemeh Zal, Solmaz Safari

Reprod Toxicol . 2020 Aug 15;96:316-326. doi: 10.1016/j.reprotox.2020.07.015. Online ahead of print.


The incidence of cancer has recently risen among the women at the reproductive age. Therefore, exposure to doxorubicin (DOX) chemotherapy has become a cause of reproductive toxicity followed by secondary destructive effects. The present study aimed to evaluate the effects of quercetin (QCT) and vitamin.E (Vit.E) on doxorubicin-induced toxicity in the ovary and uterus, and the secondary bone-related effects in a rat model. Animals were divided into six groups including control normal saline/corn oil (CON), QCT at 20 mg/Kg, Vit.E at 200 mg/Kg, DOX at accumulative 15 mg/Kg, DOX/QCT, and DOX/Vit.E. After 21 days of treatment, the alterations were analyzed in histoarchitecture, apoptosis, hormones secretion, the gene expression of aromatase and estrogen α-receptor (ER-α) in the uterine and ovarian tissues, and serum levels of bone-related factors. The results demonstrated the ameliorative effects of QCT and Vit.E on doxorubicin caused altered ovarian histology, increased apoptosis, decreased ovarian aromatase and ER-α gene expression (p-value<0.05), decreased estrogen and progesterone levels, decreased ALP (p-value<0.001), and increased osteocalcin (p-value<0.05). The findings suggested that the studied antioxidants administration could be a promising fertility preservation strategy in DOX-treated females.

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A review on vitamin E natural analogues and on the design of synthetic vitamin E derivatives as cytoprotective agents

Panagiotis Theodosis-Nobelos, Georgios Papagiouvannis, Eleni A Rekka

Mini Rev Med Chem . 2020 Aug 7. doi: 10.2174/1389557520666200807132617. Online ahead of print.


Vitamin E, essential for human health, is widely used worldwide for therapeutic or dietary reasons. The differences in the metabolism and excretion of the multiple vitamin E forms are presented in this review. The important steps that influence the kinetics of each form and the distribution and processing of vitamin E forms by the liver are considered. The antioxidant as well as non-antioxidant properties of vitamin E forms are discussed. Finally, synthetic tocopherol and trolox derivatives, based on the design of multitarget directed compounds, are reviewed. It is demonstrated that selected derivatization of vitamin E or trolox structures can produce improved antioxidants, agents against cancer, cardiovascular and neurodegenerative disorders.

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Update on the Anti-Cancer Potency of Tocotrienols and α-Tocopheryl Polyethylene Glycol 1000 Succinate on Leukemic Cell Lines

Constantina Constantinou, Christiana Charalambous, Dimitrios Kanakis, Ourania Kolokotroni, Andreas I Constantinou

Nutr Cancer . 2020 Jul 22;1-7. doi: 10.1080/01635581.2020.1797128. Online ahead of print.


The natural isoforms of vitamin E γ-tocotrienol (γ-ΤΤ) and δ-tocotrienol (δ-ΤΤ) and the synthetic derivative α-tocopheryl polyethylene glycol 1000 succinate (TPGS) have promising anticancer potency in a variety of cancer cell lines and animal models of cancer. Ongoing clinical trials are investigating the anti-tumor effectiveness of TTs in combination with chemotherapeutic agents in patients suffering from breast, colon, non-small cell lung and ovarian cancers. Despite extensive research on different types of cancer, the anticancer potency of TTs and TPGS has not been thoroughly investigated in leukemias. Given the fact that certain types of leukemias have very low survival rates and that patients suffer significantly from the toxic side effects of chemotherapeutic drugs, there is a need to develop novel treatments with increased specificity against cancer cells and reduced toxicity to the patients. The aim of this review is to report current evidence on the anticancer potency of TTs and TPGS on leukemic cells lines and to discuss future studies that could be carried out to investigate the role of these agents in the management of leukemias.

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Acylphloroglucinol and tocotrienol derivatives from the fruits of Garcinia paucinervis

Xue Tan, Fangfang Zhong, Hongli Teng, Qingqing Li, Yitong Li, Zhinan Mei, Yu Chen, Guangzhong Yang

Fitoterapia . 2020 Jul 21;146:104688. doi: 10.1016/j.fitote.2020.104688. Online ahead of print.


Three undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) and three tocotrienols derivatives, named as paucinochymol A-F (1-3 and 10-12), together with six known PPAPs, were isolated from the fruits of Garcinia paucinervis. Their structures and absolute configurations were determined by extensive NMR analysis and electronic circular dichroism (ECD) calculation methods. Paucinochymol A (1) is the first compound of this type featuring a ω-isogeranyl with tetrahydrofuran unit at C-1. Paucinochymols D and E (4-5) belong to rare tocotrienol with one glorious macrocyclic and an ortho-quinone moiety, respectively. The antiproliferative and anti-inflammatory activities of all isolates were tested. Four PPAPs exhibited weak inhibitory activities against three human cancer cell lines (HepG2, T98, MCF-7) with IC50 values ranging from 10.0 to 16.0 μM. Paucinochymol D (10) displayed moderate inhibitory effects against nitric oxide (NO) production with the IC50 value of 19.8 μM.

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Stereological and histopathological evaluation of doxorubicin-induced toxicity in female rats’ ovary and uterus and palliative effects of quercetin and vitamin E

M Samare-Najaf, F Zal, S Safari, F Koohpeyma, N Jamali

Hum Exp Toxicol . 2020 Jul 15;960327120937329. doi: 10.1177/0960327120937329. Online ahead of print


Doxorubicin (DOX) is a widely used chemotherapeutic agent with demonstrated reproductive toxicity. This study sought to determine the DOX-induced toxicity in the ovary and uterus and the preventive effects of quercetin (QCT) and vitamin E (Vit.E). Female rats were divided into six groups as follows: control, QCT (20 mg/kg), Vit.E (200 mg/kg), DOX (accumulative 15 mg/kg), DOX/QCT, and DOX/Vit.E. After 3 weeks, the toxicity of DOX in ovarian and uterine tissues and the potential palliative effects of QCT and Vit.E were evaluated by histopathological-stereological methods. The findings indicate a dramatic decline in the number of ovarian follicles (p < 0.001), ovarian and its associated structures volume, the volume of the uterus, its layers, and related structures (p < 0.05). Coadministration of QCT and Vit.E with DOX-treated rats demonstrated an alleviative effect on most of the studied parameters. Nevertheless, few adverse effects were recognized concerning these antioxidants administration (p < 0.05). In conclusion, the findings of this study support the protective role of these dietary supplements in the prevention of DOX-induced toxicity in uterine and ovarian tissues.

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Studies on the growth inhibiting and non-cytotoxic effects of tocotrienols on selected cancer cell lines

Aleksandra Szulczewska-Remi, Małgorzata Nogala-Kalucka

Acta Sci Pol Technol Aliment . Apr-Jun 2020;19(2):139-147. doi: 10.17306/J.AFS.0787.


Background: Tocotrienols found in certain plant oils, like palm, rice bran, grapeseed and annatto seeds, have been reported to possess beneficial properties for humans, including cancer prevention. Since studies on their beneficial effects on human breast cancer cells have been extensively reviewed, the current understanding of how tocotrienols affect other cancer cells deserves further research. Therefore, the aim of this study was to investigate the antiproliferative and non-cytotoxic effects of tocotrienols on human hepatoma HepG2 and colon colorectal Caco-2 cell cultures.

Methods: The cells were exposed to alpha-, beta-, gamma- or delta-tocotrienols at various concentrations and the antiproliferative activities were measured using MTS-based CellTiter 96 followed by a methylene blue assay for counting cells to evaluate the potential toxicity.

Results: The research on HepG2 showed statistically similar cytotoxic effects for both beta- and delta-T3 with no effects for alpha- and gamma-T3. Promising results were found for alpha-, beta- and gamma-T3 against CaCo-2.

Conclusions: The exact reasons for the sensitivity of liver cancer cells to tocotrienols are unknown. Inhibition is time and dose-dependent, therefore tocotrienols’ homologs show very high toxic or no effects. Tocotrienols appeared to be effective against colon cancer cells. Still, future investigation is necessary to explain the different mechanism of actions to support the antiproliferative effects of these homologs against colon cancer cells.

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Improving tumor hypoxia and radiotherapy resistance via in situ nitric oxide release strategy

Tu J, Tu K, Xu H, Wang L, Yuan X, Qin X, Kong L, Chu Q, Zhang Z

Eur J Pharm Biopharm. 2020 May;150:96-107. doi: 10.1016/j.ejpb.2020.03.003. Epub 2020 Mar 6.


Radiation therapy remains one of the main treatments for cancer. However, conventional radiotherapy not only manifests a low radiation accumulation in the tumor site, but also displays numerous negative effects. The most serious clinical problem is the radiotherapy resistance leading to cancer deterioration. As an important gaseous signal molecule, nitric oxide (NO) has been widely studied for its role in regulating angiogenesis, improving hypoxia, and inhibiting tumor growth. However, due to the unstable characteristic, the application of NO in cancer therapy is still limited. Here, we designed a micellar system formed by a NO donor, D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS)-NO, for enabling sustained NO release to efficiently deliver NO into the tumor area. TPGS-NO could accumulate in the tumor site for extended circulation, thereby releasing NO to exert antitumor effects and enhance radiotherapy effects under low-oxygen conditions. It demonstrated the increased sensitivity of radiotherapy through enhancing tumor angiogenesis appropriately reducing tumor area hypoxia, which significantly induced tumor cell apoptosis and inhibited its repair during radiation. This work may show great potential in synergistic radiotherapy against cancer by facile NO donor administration.

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Randomized, Placebo-Controlled Clinical Trial Combining Pentoxifylline-Tocopherol and Clodronate in the Treatment of Radiation-Induced Plexopathy

Delanian SE, Lenglet T, Maisonobe T, Resche-Rigon M, Pradat PF

Int J Radiat Oncol Biol Phys. 2020 May 1;107(1):154-162. doi: 10.1016/j.ijrobp.2020.01.002. Epub 2020 Jan 24.



Radiation-induced (RI) plexopathy is a rare peripheral nerve injury after radiation therapy for cancer. No treatment has been shown to slow its progression. A pentoxifylline-vitamin E combination significantly reduced RI fibrosis, and its association with clodronate (PENTOCLO) allowed healing of osteoradionecrosis and reduction of neurologic symptoms in phase 2 trials.


A placebo-controlled, double-blind trial conducted in adults with RI limb plexopathy without cancer recurrence, randomized in 2 arms to PENTOCLO (pentoxifylline 800 mg, tocopherol 1000 mg, clodronate 1600 mg 5 days per week) or triple placebo. The primary outcome measure after 18 months of treatment was the neurologic Subjective Objective Management Analytic (SOMA) score evaluating pain, paresthesia, and motor disability.


Between 2011 and 2015, 59 patients were included: 1 false inclusion (neoplastic plexopathy), 29 treated with placebo (group P), and 29 treated with the active drugs (group A); 46 patients presented an upper-limb and 12 a lower-limb plexopathy. The mean delay after irradiation was 26 ± 8 years, for patients with neurologic symptoms for 5 ± 5 years. The median global SOMA scores in the P and A groups, respectively, were 9 (range, 6-11) versus 9 (range, 8-11) at M0 and 9 (range, 5-12) versus 10 (range, 6-11) at M18 without any significant difference. Analysis of the secondary outcomes showed that SOMA score subdomains for pain and paresthesia were more affected in group A (not significant). The frequency of adverse events was similar in the 2 groups (81% of patients): slight expected vascular-gastrointestinal symptoms in A, but a large excess of RI complications (arterial stenosis).


This first randomized drug trial in RI plexopathy failed to show a beneficial effect. More studies are needed in patients with less advanced disease and fewer confounding comorbidities and with a more sensitive measure to detect a therapeutic effect.

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