γ-Tocotrienol reverses multidrug resistance of breast cancer cells through the regulation of the γ-Tocotrienol-NF-κB-P-gp axis

NF-κB signaling in therapy resistance of breast cancer: Mechanisms, approaches, and challenges

Breast cancer is the most common type of cancer and is the second leading cause of cancer-related mortality in women. Chemotherapy, targeted therapy, endocrine therapy, and radiotherapy are all effective in destroying tumor cells, but they also activate the defense and protection systems of cancer cells, leading to treatment resistance. Breast cancer is characterized by a highly inflammatory tumor microenvironment. The NF-κB pathway is essential for connecting inflammation and cancer, as well as for tumor growth and therapy resistance. An increase in NF-κB signaling boosts the growth potential of breast cancer cells and facilitates the spread of tumors to bone, lymph nodes, lungs, and liver. This review focuses on the mechanisms by which chemotherapy, targeted therapy, endocrine therapy, and radiotherapy induce breast cancer resistance through NF-κB signaling. Additionally, we investigate therapeutic regimens, including single agents or in combination with target inhibitors, plant extracts, nanomedicines, and miRNAs, that have been reported in clinical trials, in vivo, and in vitro to reverse resistance. In particular, NF-κB inhibitors combined with tamoxifen were shown to significantly increase the sensitivity of breast cancer cells to tamoxifen. Combination therapy of miRNA-34a with doxorubicin was also found to synergistically inhibit the progression of doxorubicin-resistant breast cancer by inhibiting Notch/NF-κB signaling.

Modulation of Hematopoietic Injury by a Promising Radioprotector, Gamma-Tocotrienol, in Rhesus Macaques Exposed to Partial-Body Radiation

Currently, no radioprotectors have been approved to mitigate hematopoietic injury after exposure to ionizing radiation. Acute ionizing radiation results in damage to both hematopoietic and immune system cells. Pre-exposure prophylactic agents are needed for first responders and military personnel. In this study, the ability of gamma-tocotrienol (GT3), a promising radioprotector and antioxidant, to ameliorate partial-body radiation-induced damage to the hematopoietic compartment was evaluated in a nonhuman primate (NHP) model. A total of 15 rhesus NHPs were divided into two groups, and were administered either GT3 or vehicle 24 h prior to 4 or 5.8 Gy partial-body irradiation (PBI), with 5% bone marrow (BM) sparing. Each group consisted of four NHPs, apart from the vehicle-treated group exposed to 5.8 Gy, which had only three NHPs. BM samples were collected 8 days prior to irradiation in addition to 2, 7, 14, and 30 days postirradiation. To assess the clonogenic ability of hematopoietic stem and progenitor cells (HSPCs), colony forming unit (CFU) assays were performed, and lymphoid cells were immunophenotyped using flow cytometry. As a result of GT3 treatment, an increase in HSPC function was evident by an increased recovery of CFU-granulocyte macrophages (CFU-GM). Additionally, GT3 treatment was shown to increase the percentage of CD34+ cells, including T and NK-cell subsets. Our data further affirm GT3's role in hematopoietic recovery and suggest the need for its further development as a prophylactic radiation medical countermeasure.

The Effects of Tocotrienol on Gut Microbiota: A Scoping Review

Gut dysbiosis has been associated with many chronic diseases, such as obesity, inflammatory bowel disease, and cancer. Gut dysbiosis triggers these diseases through the activation of the immune system by the endotoxins produced by gut microbiota, which leads to systemic inflammation. In addition to pre-/pro-/postbiotics, many natural products can restore healthy gut microbiota composition. Tocotrienol, which is a subfamily of vitamin E, has been demonstrated to have such effects. This scoping review presents an overview of the effects of tocotrienol on gut microbiota according to the existing scientific literature. A literature search to identify relevant studies was conducted using PubMed, Scopus, and Web of Science. Only original research articles which aligned with the review's objective were examined. Six relevant studies investigating the effects of tocotrienol on gut microbiota were included. All of the studies used animal models to demonstrate that tocotrienol altered the gut microbiota composition, but none demonstrated the mechanism by which this occurred. The studies induced diseases known to be associated with gut dysbiosis in rats. Tocotrienol partially restored the gut microbiota compositions of the diseased rats so that they resembled those of the healthy rats. Tocotrienol also demonstrated strong anti-inflammatory effects in these animals. In conclusion, tocotrienol could exert anti-inflammatory effects by suppressing inflammation directly or partially by altering the gut microbiota composition, thus achieving its therapeutic effects.

Strategies to overcome cancer multidrug resistance (MDR) through targeting P-glycoprotein (ABCB1): An updated review

The emergence of multidrug resistance (MDR) in malignant tumors is one of the leading threats encountered currently in many chemotherapeutic agents. The overexpression of the ATP-binding cassette (ABC) transporters is involved in MDR. P-glycoprotein (P-gp)/ABCB1 is a member of the ABC transporter family that significantly increases the efflux of various anticancer drugs from tumor cells. Therefore, targeting P-gp with small molecule inhibitors is an effective therapeutic strategy to overcome MDR. Over the past four decades, diverse compounds with P-gp inhibitory activity have been identified to sensitize drug-resistant cells, but none of them has been proven clinically useful to date. Research efforts continue to discover an effective approach for circumventing MDR. This review has provided an overview of the most recent advances (last three years) in various strategies for circumventing MDR mediated by P-gp. It may be helpful for the scientists working in the field of drug discovery to further synthesize and discover new chemical entities/therapeutic modalities with less toxicity and more efficacies to overcome MDR in cancer chemotherapy.

A Novel Electrochemical Differentiation between Exosomal-RNA of Breast Cancer MCF7 and MCF7/ADR-Resistant Cells

Cancer is considered one of the most burdensome diseases affecting lives and, hence, the economy. Breast cancer is one of the most common types of cancer. Patients with breast cancer are divided into two groups: one group responds to the chemotherapy, and the other group resists the chemotherapy. Unfortunately, the group which resists the chemotherapy is still suffering the pain associated with the severe side effects of the chemotherapy. Therefore, there is a critical need for a method to differentiate between both groups before the administration of the chemotherapy. Exosomes, the recently discovered nano-vesicles, are often used as cancer diagnostic biomarkers as their unique composition allows them to represent their parental cells, which makes them promising indicators for tumor prognosis. Exosomes contain proteins, lipids, and RNA that exist in most body fluids and are expelled by multiple cell types, including cancer cells. Furthermore, exosomal RNA has been significantly used as a promising biomarker for tumor prognosis. Herein, we have developed an electrochemical system that could successfully differentiate between MCF7 and MCF7/ADR depending on the exosomal RNA. The high sensitivity of the proposed electrochemical assay opens the door for further investigation that will address the other type of cancer cells.

Role of natural P-gp inhibitor in the effective delivery for chemotherapeutic agents

Multi-drug resistance has shown to be one of the leading threats faced currently in many chemotherapeutic agents. Permeability glycoprotein (P-gp) is an efflux transporter in membrane, an integral part of ATP-binding cassette (ABC) transporters widely distributed in the body for cellular uptake. It is present enormously in cancerous cells and is in charge of generating transporter mediated resistance to treatments of tumorous cells in addition to blocking the entry of chemotherapeutic drugs into the cell. Natural P-gp inhibitors are derived from natural plant sources possessing basic structures like alkaloids, flavonoids, phenolics, terpenoids, saponins, sapogenins, sterols, coumarins and miscellaneous structures acting on P-gp substrate for inhibition of multi-drug resistance via inhibiting the efflux pump. They do not depict their action on the healthy cells and thus it is proven to be more effective and less toxic than synthetic P-gp inhibitor leading to enhancement in bioavailability of chemotherapeutic drugs. The significant objective of the present review is surfing through the impact of natural P-gp inhibitors having basic structures derived from the plant sources and how it inhibits the resistance of chemotherapeutic drugs together with how well it delivers chemotherapy medicines.

Effect of vitamins C and E on cancer survival; a systematic review

PURPOSE

Association between vitamins C (VC)/ E (VE) and cancer survival is inconsistent. This systematic review is aimed to summarize trials for effects of VC/VE on cancer survival.

METHODS

Relevant English trials were retrieved from PubMed, Cochrane Library, Embase, Web of Science, Scopus databases, and Clinicaltrials.gov through 21/June/2022. Inclusion criteria were all trials which assessed sole/combinations intake of VC/VE on survival rate, mortality, or remission of any cancer. Exclusion criteria were observational and animal studies.

RESULTS

We reached 30 trials conducted on 38,936 patients with various cancers. Due to severe methodological heterogeneity, meta-analysis was impossible. High dose VC + chemotherapy or radiation was safe with an overall survival (OS) 182 days - 21.5 months. Sole oral or intravenous high dose VC was safe with non-significant change in OS (2.9-8.2 months). VE plus chemotherapy was safe, resulted in stabling diseases for 5 years in 70- 86.7% of patients and OS 109 months. It was found 60% and 16% non-significant reductions in adjusted hazard ratio (HR) deaths or recurrence by 200 mg/d tocotrienol + tamoxifen in breast cancer, respectively. Sole intake of 200-3200 mg/d tocotrienol before resectable pancreatic cancer was safe and significantly increased cancer cells' apoptosis. Combination VC and VE was non-significantly reduced 7% in rate of neoplastic gastric polyp.

CONCLUSION

Although our study is supported improvement of survival and progression rates of cancers by VC/VE, more high quality trials with large sample sizes are required to confirm.

PROSPERO REGISTRATION NUMBER

CRD42020152795.

Simultaneous Determination of Retinols and Tocols in Egg and Milk Products Based on RP-HPLC Linked with Fluorescent and Photodiode Array

In this paper, we built a method of verifying the 4 retinols of vitamin A and 8 tocopherol isomers of vitamin E in the food industry based on RP-HPLC-PDA-FLR. The effect of laboratory light conditions on the target components was considered for the first time, and it was found that the loss rate of the target components was the smallest in the case of a white laboratory bench with red or LED light in the dark room. There was no finding of extraction recoveries of the target components with a significant difference under different saponification conditions. Meanwhile, it was found that using ethyl acetate/n-hexane mixed solvent as the extraction solvent could ensure the effective extraction of the target components. Finally, baseline separation of 12 components was achieved within 45 min using the C30 column. With the help of methodological verification, we found that the recovery rate ranged from 76.45% to 93.52%, and RSD was between 0.19% and 12.99%; the Limit of Detection minimum value was 0.01 mg/100 g and the Limit of Quantitation minimum value was 0.03 mg/100 g. The detection method was successfully applied to the distribution detection of 4 kinds of retinols and 8 kinds of vitamin E in egg and dairy products and provided technical support for the accurate nutritional evaluation of vitamin A and vitamin E.

Revisiting the therapeutic potential of tocotrienol

The therapeutic potential of the tocotrienol group stems from its nutraceutical properties as a dietary supplement. It is largely considered to be safe when consumed at low doses for attenuating pathophysiology as shown by animal models, in vitro assays, and ongoing human trials. Medical researchers and the allied sciences have experimented with tocotrienols for many decades, but its therapeutic potential was limited to adjuvant or concurrent treatment regimens. Recent studies have focused on targeted drug delivery by enhancing the bioavailability through carriers, self-sustained emulsions, nanoparticles, and ethosomes. Epigenetic modulation and computer remodeling are other means that will help increase chemosensitivity. This review will focus on the systemic intracellular anti-cancer, antioxidant, and anti-inflammatory mechanisms that are stimulated and/or regulated by tocotrienols while highlighting its potent therapeutic properties in a diverse group of clinical diseases.

Resveratrol Inhibits Pseudorabies Virus Replication by Targeting IE180 Protein

Resveratrol is a natural polyphenolic product in red wine and peanuts and has many pharmacological activities in humans. Our previous studies showed that resveratrol has good antiviral activity against the pseudorabies virus (PRV). However, little is known about the antiviral mechanism of resveratrol against PRV. In this study, we found that resveratrol inhibited the nuclear localization of IE180 protein, which is an important step for activating early/late genes transcription. Interestingly, the results show that resveratrol inhibited the activity of IE180 protein by dual-luciferase assay. Furthermore, molecular docking analysis shows that resveratrol could bind to the Thr601, Ser603, and Pro606 of IE180 protein. Point mutation assay confirmed that resveratrol lost its inhibition activity against the mutant IE180 protein. The results demonstrate that resveratrol exerts its antiviral activity against PRV by targeting the Thr601/Ser603/Pro606 sites of IE180 protein and inhibiting the transcriptional activation activity of IE180 protein. This study provides a novel insight into the antiviral mechanism of resveratrol against herpes viruses.

Tumor Glucose and Fatty Acid Metabolism in the Context of Anthracycline and Taxane-Based (Neo)Adjuvant Chemotherapy in Breast Carcinomas

Breast cancer is characterized by considerable metabolic diversity. A relatively high percentage of patients diagnosed with breast carcinoma do not respond to standard-of-care treatment, and alteration in metabolic pathways nowadays is considered one of the major mechanisms responsible for therapeutic resistance. Consequently, there is an emerging need to understand how metabolism shapes therapy response, therapy resistance and not ultimately to analyze the metabolic changes occurring after different treatment regimens. The most commonly applied neoadjuvant chemotherapy regimens in breast cancer contain an anthracycline (doxorubicin or epirubicin) in combination or sequentially administered with taxanes (paclitaxel or docetaxel). Despite several efforts, drug resistance is still frequent in many types of breast cancer, decreasing patients’ survival. Understanding how tumor cells rapidly rewire their signaling pathways to persist after neoadjuvant cancer treatment have to be analyzed in detail and in a more complex system to enable scientists to design novel treatment strategies that target different aspects of tumor cells and tumor resistance. Tumor heterogeneity, the rapidly changing environmental context, differences in nutrient use among different cell types, the cooperative or competitive relationships between cells pose additional challenges in profound analyzes of metabolic changes in different breast carcinoma subtypes and treatment protocols. Delineating the contribution of metabolic pathways to tumor differentiation, progression, and resistance to different drugs is also the focus of research. The present review discusses the changes in glucose and fatty acid pathways associated with the most frequently applied chemotherapeutic drugs in breast cancer, as well the underlying molecular mechanisms and corresponding novel therapeutic strategies.

Chronic myeloid leukemia: cytogenetics and molecular biology’s part in the comprehension and management of the pathology and treatment evolution

Background

Chronic myelogenous leukemia (CML) is a type of blood cancer that affects hematopoietic stem cells and is often characterized by the presence of the Philadelphia chromosome. The Philadelphia chromosome encodes for a protein with high tyrosine kinase activity which acts as a tumorigenic factor.

Main body

This review article reports an update on the pathophysiology of CML and highlights the role of cytogenetic and molecular biology in screening, diagnosis, therapeutic monitoring as well as evaluating patients’ response to treatment. Additionally, these genetic tests allow identifying additional chromosomal abnormalities (ACA) and BCR-ABL tyrosine kinase domain mutations in intolerant or resistant patients. Thus, therapeutic advances have enabled this pathology to become manageable and almost curable in its clinical course. The scientific literature search used in the synthesis of this paper was carried out in the PubMed database, and the figures were generated using online software named BioRender.

Conclusion

The role of cytogenetic and molecular biology is crucial for the diagnosis and medical monitoring of patients. In-depth knowledge of molecular mechanisms of the BCR-ABL kinase facilitated the development of new targeted therapies that have improved the vital prognosis in patients. However, the emergence of ACA and new mutations resistant to tyrosine kinase inhibitors constitutes a real challenge in the quest for adequate therapy.

Differential Mechanisms of Action and Efficacy of Vitamin E Components in Antioxidant Cytoprotection of Human Retinal Pigment Epithelium

The purpose of this study was to determine if different vitamin E components exhibit similar efficacy and mechanism of action in protecting Retinal pigment epithelium (RPE) cells from oxidative damage. We hypothesized that α-tocopherol (αT) is unique among vitamin E components in its cytoprotective mechanism of action against oxidative stress in RPE cells and that it requires protein synthesis for optimal antioxidant effect. We used cell viability assays, fluorescent chemical labeling of DNA and actin and immuno-labeling of the antioxidant proteins Nrf2 and Sod2 and of the tight junction protein, ZO-1, and confocal microscopy to determine the effects of αT and γT against oxidative stress in immortalized human RPE cells (hTERT-RPE). Using the four main vitamin E components, αT, γT, δ-tocopherol (δT) and α-tocotrienol (αTr), we ascertained that they exhibit similar, but not identical, antioxidant activity as αT when used at equimolar concentrations. In addition, we determined that the exposure time of RPE cells to α-tocopherol is critical for its ability to protect against oxidative damage. Lastly, we determined that αT, but not γT, partially requires the synthesis of new proteins within a 24-h period and prior to exposure to tBHP for optimal cytoprotection. We conclude that, unlike γT and δT, αT appears to be unique in its requirement for transport and/or signaling for it to be an effective antioxidant. As a result, more focus should be paid to which vitamin E components are used for antioxidant interventions.

Cardamonin inhibits the expression of P-glycoprotein and enhances the anti-proliferation of paclitaxel on SKOV3-Taxol cells

Paclitaxel is widely used in the first-line treatment of ovarian cancer. Nevertheless, the development of acquired resistance to paclitaxel is a major obstacle for the therapy in clinic. Cardamonin is a novel anticancer chalcone which exhibits a wide range of pharmacological activities. However, the effect of cardamonin on paclitaxel-resistant ovarian cancer cells and its underlying molecular mechanisms are unknown. Here, we revealed whether cardamonin had a resensitivity for paclitaxel and furtherly explored the underlying mechanisms on SKOV3-Taxol cells. Our results showed that cardamonin combined with paclitaxel had a synergistic effect of anti-proliferation in SKOV3-Taxol cells, and CI was less than one. Cells apoptosis and G2/M phase arrest were enhanced by cardamonin with paclitaxel in a concentration-dependent way on SKOV3-Taxol cells (P < 0.05). Cardamonin significantly increased drug accumulation in SKOV3-Taxol cells (P < 0.05). Similar to verapamil, cardamonin decreased MDR1 mRNA and P-gp expression (P < 0.05). Cardamonin restrained NF-κB activation in SKOV3-Taxol cells (P < 0.05). Inhibitory effect of P-gp and NF-κB p65 (nuclear protein) expression was enhanced by cardamonin combined with PDTC, a NF-κB inhibitor. Cardamonin significantly inhibited the upregulation of NF-κB p65 (nuclear protein) and P-gp expression induced by TNF-α (P < 0.05). Taken together, cardamonin enhanced the effect of paclitaxel on inhibiting cell proliferation, inducing apoptosis and G2/M phase arrest, and then strengthened the cytotoxic effect of paclitaxel in SKOV3-Taxol cells. The mechanism might be involved in inhibition of P-gp efflux pump, reducing MDR1 mRNA and P-gp expression by cardamonin via suppression of NF-κB activation in SKOV3-Taxol cells.

Targeted inhibition of TAK1 abrogates TGFβ1 non-canonical signaling axis, NFκB/Smad7 inhibiting human endometriotic cells proliferation and inducing cell death involving autophagy

Transforming growth factor (TGFβ) is known to play a major role in establishment and maintenance of endometriosis as reported by our group earlier, the underlying mechanism remains to be explored. We deciphered the involvement of TAK1 in TGFβ1- induced cellular responses and delineated the signaling mechanism in human endometriotic cells. The endometriotic cells showed elevated expression of TGFβ1 signaling-effector molecules. TGFβ1 exposure to endometriotic cells induced the expression of the downstream target molecules indicating that TGFβ1 is implicated in the commencement ofTAK1/NFκB-p65/Smad7 cascade. The silencing of TAK1 in endometriotic cells attenuated the TGFβ1 -induced NFκB transcriptional activation and nuclear translocation of NFκB-p65 subunit. The pharmacological inhibition of NFκB by QNZ or knockdown of TAK1 reduced the expression of Smad7 and Cox2. The knockdown of TAK1 in endometriotic cells showed G1 phase cell-cycle arrest and showed low BrdU-incorporation in the presence of TGFβ1. The inhibition of TAK1 attenuated the TGFβ1 signaling activation indicating that TAK1 is a crucial mediator for TGFβ1 action in endometriotic cells. The exposure of endometriotic cells to TAK1 inhibitor, celastrol caused activation of caspase-3 and -9 that led to PARP cleavage and induced apoptosis. Simultaneously, autophagy occurred in celastrol-treated and TAK1-silenced cells as was evidenced by the formation of autophagosome and the increased expression of autophagic markers. Thus, TAK1 activation appears to protect the growth of endometriotic cells by suppressing the cell death process. Overall, our study provided the evidence that of TAK1 significant in the endometriotic cell regulation and mediates a functional cross-talk between TGFβ1 and NFκB-p65 that promotes the growth and inflammatory response in endometriotic cells.

Caffeic acid and its derivatives as potential modulators of oncogenic molecular pathways: New hope in the fight against cancer

As a phenolic acid compound, caffeic acid (CA) can be isolated from different sources such as tea, wine and coffee. Caffeic acid phenethyl ester (CAPE) is naturally occurring derivative of CA isolated from propolis. This medicinal plant is well-known due to its significant therapeutic impact including its effectiveness as hepatoprotective, neuroprotective and anti-diabetic agent. Among them, anti-tumor activity of CA has attracted much attention, and this potential has been confirmed both in vitro and in vivo. CA can induce apoptosis in cancer cells via enhancing ROS levels and impairing mitochondrial function. Molecular pathways such as PI3K/Akt and AMPK with role in cancer progression, are affected by CA and its derivatives in cancer therapy. CA is advantageous in reducing aggressive behavior of tumors via suppressing metastasis by inhibiting epithelial-to-mesenchymal transition mechanism. Noteworthy, CA and CAPE can promote response of cancer cells to chemotherapy, and sensitize them to chemotherapy-mediated cell death. In order to improve capacity of CA and CAPE in cancer suppression, it has been co-administered with other anti-tumor compounds such as gallic acid and p-coumaric acid. Due to its poor bioavailability, nanocarriers have been developed for enhancing its ability in cancer suppression. These issues have been discussed in the present review with a focus on molecular pathways to pave the way for rapid translation of CA for clinical use.