Challenges and Opportunities of Nanotechnology as Delivery Platform for Tocotrienols in Cancer Therapy

Vitamin E nomenclature. Is RRR-α-tocopherol the only vitamin E?

It has generally been accepted that vitamin E refers to a group of tocochromanols, α-, β-, γ-, and δ-tocopherols and the corresponding four tocotrienols. Recently, Azzi and colleagues proposed to restrict the term vitamin E only to RRR-α-tocopherol, not to other tocopherols and tocotrienols (Azzi A et al. Free Radic Biol Med. 2023; 207:178-180. doi: 10.1016/j.freeradbiomed.2023.06.029). The aim of this paper is to express our opinion on the nomenclature of vitamin E based on available scientific data. In our opinion, it would be inappropriate to exclude all the tocochromanols other than RRR-α-tocopherol from the vitamin E group at this stage when the molecular mechanisms showing how vitamin E deficiency causes diseases such as ataxia and how vitamin E prevents/reverses such diseases are not elucidated. Understanding of whole functions of tocochromanols including underlying mechanisms and dynamics is essential before revision of currently accepted definition of vitamin E. The potential roles of γ-tocopherol and tocotrienols are discussed despite whether they are vitamin function should be clarified in the future studies.

Advancements and prospects of lipid-based nanoparticles: dual frontiers in cancer treatment and vaccine development

Cancer is a complex heterogeneous disease that poses a significant public health challenge. In recent years, lipid-based nanoparticles (LBNPs) have expanded drug delivery and vaccine development options owing to their adaptable, non-toxic, tuneable physicochemical properties, versatile surface functionalisation, and biocompatibility. LBNPs are tiny artificial structures composed of lipid-like materials that can be engineered to encapsulate and deliver therapeutic agents with pinpoint accuracy. They have been widely explored in oncology; however, our understanding of their pharmacological mechanisms, effects of their composition, charge, and size on cellular uptake, tumour penetration, and how they can be utilised to develop cancer vaccines is still limited. Hence, we reviewed LBNPs' unique characteristics, biochemical features, and tumour-targeting mechanisms. Furthermore, we examined their ability to enhance cancer therapies and their potential contribution in developing anticancer vaccines. We critically analysed their advantages and challenges impeding swift advancements in oncology and highlighted promising avenues for future research.

Carbohydrate polymers-based surface modified nano delivery systems for enhanced target delivery to colon cancer - A review

Carbohydrate polymers-based surface-modified nano-delivery systems have gained significant attention in recent years for enhancing targeted delivery to colon cancer. These systems leverage carbohydrate polymers' unique properties, such as biocompatibility, biodegradability, and controlled release. These properties make them suitable candidates for drug delivery applications. Nano-delivery systems loaded with bioactive compounds are well-studied for targeted colorectal cancer delivery. However, those drugs' target reach is still limited in various nano-delivery systems. To overcome this limitation, surface modification of nanoparticles with carbohydrate polymers like chitosan, pectin, alginate, and guar gum showed enhanced target-reaching capacity along with enhanced anticancer efficacy. Recently, a chitosan-decorated PLGA nanoparticle was constructed with tannic acid and vitamin E and showed long-term release of specific targets along with higher anticancer efficacy. Similarly, Chitosan-conjugated glucuronic acid-coated silica nanoparticles loaded with capecitabine were studied against colon cancer and found to be the pH-responsive controlled release of capecitabine with higher anticancer efficacy. Surface-modified carbohydrate polymers have promising potential for improving colon cancer target delivery. By leveraging the unique properties of these polymers, such as surface modification, pH responsiveness, mucoadhesion, controlled drug release, and combination therapy, researchers are working toward developing more effective and targeted treatment strategies for colon cancer.

Effect of nano-delivery systems on the bioavailability and tissue biodistribution of vitamin E tocotrienols

Vitamin E is one of the most important essential vitamins to support the regulation of oxidative stress in human body. Tocotrienols are part of the vitamin E family. The potentials of tocotrienols as nutraceutical ingredient are largely understated due to low oral bioavailability, which is a common problem associated with fat-soluble bioactive compounds. Nanoencapsulation technology offers innovative solutions to enhance the delivery mechanisms of these compounds. In this study, the effect of nanoencapsulation on the oral bioavailability and tissue distribution of tocotrienols were investigated using two types of formulations, i.e. nanovesicles (NV-T3) and solid lipid nanoparticles (NP-T3). At least 5-fold increment in maximum plasma concentrations, evident with dual-peak pharmacokinetic profiles, were observed after oral administration of nano-encapsulated tocotrienols. Plasma tocotrienol composition showed a shift from α-tocotrienol dominant in control group (Control-T3) to γ-tocotrienol dominant after nanoencapsulation. Tissue distribution of tocotrienols was found to be strongly influenced by the type of nanoformulation. Both nanovesicles (NV-T3) and nanoparticles (NP-T3) showed elevated accumulation in the kidneys and liver (5-fold) compared to control group while selectivity for α-tocotrienol was evident for NP-T3. In brain and liver of rats given NP-T3, α-tocotrienol emerged as the dominant congener (>80%). Acute oral administration of nanoencapsulated tocotrienols did not show signs of toxicity. The study concluded enhanced bioavailability and selective tissue accumulation of tocotrienol congeners when delivered via nanoencapsulation.

Niosome as an Effective Nanoscale Solution for the Treatment of Microbial Infections

Numerous disorders go untreated owing to a lack of a suitable drug delivery technology or an appropriate therapeutic moiety, particularly when toxicities and side effects are a major concern. Treatment options for microbiological infections are not fulfilled owing to significant adverse effects or extended therapeutic options. Advanced therapy options, such as active targeting, may be preferable to traditional ways of treating infectious diseases. Niosomes can be defined as microscopic lamellar molecules formed by a mixture of cholesterol, nonionic surfactants (alkyl or dialkyl polyglycerol ethers), and sometimes charge-inducing agents. These molecules comprise both hydrophilic and hydrophobic moieties of varying solubilities. In this review, several pathogenic microbes such as Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Plasmodium, Leishmania, and Candida spp. have been evaluated. Also, the development of a proper niosomal formulation for the required application was discussed. This review also reviews that an optimal formulation is dependent on several aspects, including the choice of nonionic surfactant, fabrication process, and fabrication parameters. Finally, this review will give information on the effectiveness of niosomes in treating acute microbial infections, the mechanism of action of niosomes in combating microbial pathogens, and the advantages of using niosomes over other treatment modalities.

Vitamin E in the management of pancreatic cancer: A scoping review

Pancreatic cancer is the leading cause of cancer mortality worldwide. Research investigating effective management strategies for pancreatic cancer is ongoing. Vitamin E, consisting of both tocopherol and tocotrienol, has demonstrated debatable effects on pancreatic cancer cells. Therefore, this scoping review aims to summarize the effects of vitamin E on pancreatic cancer. In October 2022, a literature search was conducted using PubMed and Scopus since their inception. Original studies on the effects of vitamin E on pancreatic cancer, including cell cultures, animal models and human clinical trials, were considered for this review. The literature search found 75 articles on this topic, but only 24 articles met the inclusion criteria. The available evidence showed that vitamin E modulated proliferation, cell death, angiogenesis, metastasis and inflammation in pancreatic cancer cells. However, the safety and bioavailability concerns remain to be answered with more extensive preclinical and clinical studies. More in-depth analysis is necessary to investigate further the role of vitamin E in the management of pancreatic cancers.

Natural Compounds: Co-Delivery Strategies with Chemotherapeutic Agents or Nucleic Acids Using Lipid-Based Nanocarriers

Cancer is one of the leading causes of death, and latest predictions indicate that cancer- related deaths will increase over the next few decades. Despite significant advances in conventional therapies, treatments remain far from ideal due to limitations such as lack of selectivity, non-specific distribution, and multidrug resistance. Current research is focusing on the development of several strategies to improve the efficiency of chemotherapeutic agents and, as a result, overcome the challenges associated with conventional therapies. In this regard, combined therapy with natural compounds and other therapeutic agents, such as chemotherapeutics or nucleic acids, has recently emerged as a new strategy for tackling the drawbacks of conventional therapies. Taking this strategy into consideration, the co-delivery of the above-mentioned agents in lipid-based nanocarriers provides some advantages by improving the potential of the therapeutic agents carried. In this review, we present an analysis of the synergistic anticancer outcomes resulting from the combination of natural compounds and chemotherapeutics or nucleic acids. We also emphasize the importance of these co-delivery strategies when reducing multidrug resistance and adverse toxic effects. Furthermore, the review delves into the challenges and opportunities surrounding the application of these co-delivery strategies towards tangible clinical translation for cancer treatment.

Exploring the anti-inflammatory activities, mechanism of action and prospective drug delivery systems of tocotrienol to target neurodegenerative diseases

A major cause of death in the elderly worldwide is attributed to neurodegenerative diseases, such as AD (Alzheimer's disease), PD (Parkinson's disease), ALS (Amyotrophic lateral sclerosis), FRDA (Friedreich's ataxia), VaD (Vascular dementia) etc. These can be caused due to multiple factors such as genetic, physiological problems like stroke or tumor, or even external causes like viruses, toxins, or chemicals. T3s (tocotrienols) exhibit various bioactive properties where it acts as an antioxidant, anti-inflammatory, anti-tumorigenic, and cholesterol lowering agent. Since T3 interferes with and influences several anti-inflammatory mechanisms, it aids in combating inflammatory responses that lead to disease progression. T3s are found to have a profound neuroprotective ability, however, due to their poor oral bioavailability, their full potential could not be exploited. Hence there is a need to explore other drug delivery techniques, especially focusing on aspects of nanotechnology. In this review paper we explore the anti-inflammatory mechanisms of T3 to apply it in the treatment of neurodegenerative diseases and also discusses the possibilities of nano methods of administering tocotrienols to target neurodegenerative diseases.

The anti-tumor and renoprotection study of E-[c(RGDfK)2]/folic acid co-modified nanostructured lipid carrier loaded with doxorubicin hydrochloride/salvianolic acid A

Background

Poor in vivo targeting of tumors by chemotherapeutic drugs reduces their anti-cancer efficacy in the clinic. The discovery of over-expressed components on the tumor cell surface and their specific ligands provide a basis for targeting tumor cells. However, the differences in the expression levels of these receptors on the tumor cell surface limit the clinical application of anti-tumor preparations modified by a single ligand. Meanwhile, toxicity of chemotherapeutic drugs leads to poor tolerance to anti-tumor therapy. The discovery of natural active products antagonizing these toxic side effects offers an avenue for relieving cancer patients’ pain during the treatment process. Since the advent of nanotechnology, interventions, such as loading appropriate drug combinations into nano-sized carriers and multiple tumor-targeting functional modifications on the carrier surface to enhance the anti-tumor effect and reduce toxic and side effects, have been widely used for treating tumors.

Results

Nanocarriers containing doxorubicin hydrochloride (DOX) and salvianolic acid A (Sal A) are spherical with a diameter of about 18 nm; the encapsulation efficiency of both DOX and salvianolic acid A is greater than 80%. E-[c(RGDfK)2]/folic acid (FA) co-modification enabled nanostructured lipid carriers (NLC) to efficiently target a variety of tumor cells, including 4T1, MDA-MB-231, MCF-7, and A549 cells in vitro. Compared with other preparations (Sal A solution, NLC-Sal A, DOX solution, DOX injection, Sal A/DOX solution, NLC-DOX, NLC-Sal A/DOX, and E-[c(RGDfK)2]/FA-NLC-Sal A/DOX) in this experiment, the prepared E-[c(RGDfK)2]/FA-NLC-Sal A/DOX had the best anti-tumor effect. Compared with the normal saline group, it had the highest tumor volume inhibition rate (90.72%), the highest tumor weight inhibition rate (83.94%), led to the highest proportion of apoptosis among the tumor cells (61.30%) and the lowest fluorescence intensity of proliferation among the tumor cells (0.0083 ± 0.0011). Moreover, E-[c(RGDfK)2]/FA-NLC-Sal A/DOX had a low level of nephrotoxicity, with a low creatinine (Cre) concentration of 52.58 μmoL/L in the blood of mice, and no abnormalities were seen on pathological examination of the isolated kidneys at the end of the study. Sal A can antagonize the nephrotoxic effect of DOX. Free Sal A reduced the Cre concentration of the free DOX group by 61.64%. In NLC groups, Sal A reduced the Cre concentration of the DOX group by 42.47%. The E-[c(RGDfK)2]/FA modification reduced the side effects of the drug on the kidney, and the Cre concentration was reduced by 46.35% compared with the NLC-Sal A/DOX group. These interventions can potentially improve the tolerance of cancer patients to chemotherapy.

Conclusion

The E-[c(RGDfK)2]/FA co-modified DOX/Sal A multifunctional nano-drug delivery system has a good therapeutic effect on tumors and low nephrotoxicity and is a promising anti-cancer strategy.

Graphical Abstract

Effective Cancer Management: Inimitable Role of Phytochemical Based Nano- Formulations

BACKGROUND

Global cancer statistics defines the severity of disease even after significant research worldwide.

PROBLEM

Failure of the currently available treatment approaches, including surgery, radiation therapy and traditional chemotherapy.

AIM

The aim of this review is to discuss the role of phytochemical based nano-formulations for treatment of cancer.

DISCUSSION

In the past few decades, phytochemicals have gained popularity for acting as a potential anticancer treatment with low systemic toxicity, especially in terms of cell cycle control and cancer cell killing. Natural resources, with their immense structural variety, serve as a vital source of fresh, therapeutically useful new chemical entities for the treatment of cancer. Vinca alkaloids (VCR), vinblastine, vindesine, vinorelbine, taxanes (PTX), podophyllotoxin and its derivatives (etoposide (ETP), teniposide, camptothecin (CPT) and its derivatives (topotecan, irinotecan), anthracyclines (doxorubicin, daunorubicin, epirubicin, idarubicin, as natural products or their derivatives account for half of all anticancer drugs approved worldwide, and they have been developed utilising the knowledge learned from the natural small molecules or macromolecules. Trabectedin, an epothilone derivative, ixabepilone, and temsirolimus, three new anticancer medications launched in 2007, were derived from microbial origins. Current therapy regimens require selective drug targeting to enhance efficacy against cancer cells while normal cells remain unharmed. Modified medications and systems for drug delivery based on nanotechnology are in the process of being explored and launched in the industry for enhanced therapy and management of cancer, along with promising outcomes. Many obstacles related to cancer cell drug delivery can be overcome by using nano-particulate drug carriers, including enhancing the stability and solubility of the drug, prolonging half-lives of the drug in the blood, decreasing side effects to undesired organs, and increasing medication concentration at the desired site. The scientific initiatives and studies concerning the use of nanotechnology for some selective compounds derived from plants are discussed in this review article.

CONCLUSION

The present review highlights the phytochemical-based nanoformulations and their strategies in the development of novel systems of drug delivery such as nano-liposomes, functionalized nanoparticles (NPs), and polymer nano-conjugates, SNEDDS (Self nano emulsifying drug delivery system) as this review paper depicts, as well as their rewards over conventional systems of drug delivery, as evidenced by improved biological activity depicted in their in vitro and in vivo anticancer assays.

Magneto-Endosomalytic Therapy for Cancer

A remarkably simple yet effective mode of cancer treatment is reported by repurposing clinically approved magnetic nanoparticles (MNPs). Intracellular nanoparticle self-assembly directed by static parallel magnetic fields leads to cell death in targeted tissues while leaving other cells and organs intact. This simple concept opens a new avenue to treat cancer, capitalizing on nanosciences and the nanoparticle (NP) design principles accumulated in the past decades.

Animal protein-plant protein composite nanospheres for dual-drug loading and synergistic cancer therapy

The co-delivery of multiple drugs using one drug carrier is a viable strategy to optimize drug dosage and reduce the side effects in chemotherapy. Herein, a hydrophilic animal protein (silk fibroin) and a hydrophobic plant protein (zein) were selected for preparing a composite drug carrier. Adapting our previously developed method for the preparation of regenerated silk fibroin (RSF) nanospheres, we prepared RSF/zein nanospheres that displayed an interesting structure including a single central hole. The particle size of the RSF/zein nanospheres was regulated from 150 to 460 nm by varying the preparation conditions, implying that such a drug carrier is suitable for both intravenous administration and lymphatic chemotherapy. Two anti-cancer drugs with different target sites, paclitaxel (PTX) and curcumin (CUR), were selected for the preparation of dual-drug-loaded CUR/PTX@RSF/zein nanospheres. Both drugs achieved a high loading capacity in the RSF/zein nanospheres, i.e., 8.2% for PTX and 12.1% for CUR. Subsequently, the encapsulated PTX and CUR were released from the RSF/zein nanospheres in a sustained manner for at least 7 days. Importantly, these dual-drug-loaded RSF/zein nanospheres exhibited a considerable synergistic therapeutic effect, showing more efficient suppression of in vitro cancer cell growth than free PTX or CUR, a combination of free PTX and CUR, or single-drug-loaded nanospheres. Therefore, the CUR/PTX@RSF/zein nanospheres developed in this study hold great potential for combination chemotherapy in future clinical applications.

The effect of AS1411 surface density on the tumor targeting properties of PEGylated silver nanotriangles

Aim: To determine the optimal AS1411 density on polyethylene glycol (PEG)ylated silver nanotriangles (PNTs) for targeting breast cancer cells. Methods: PNTs modified with different AS1411 densities (ANTs) were constructed, characterized and evaluated for their targeting properties in breast cancer cells and a mouse model of breast cancer. Results: AS1411 was successfully conjugated to PNTs. The accumulation and cellular uptake of 10-ANTs were the highest. 10-ANTs plus near-IR laser irradiation displayed the greatest inhibitory effect on cell viability. However, 5-ANTs had the highest accumulation in tumor tissues. When combined with NIR laser, 5-ANTs exhibited the best in vivo photothermal therapy effect. Conclusion: The optimal AS1411 densities at the cellular and animal levels were 10% and 5%, respectively.

Polydatin gold nanoparticles potentiate antitumor effect of doxorubicin in Ehrlich ascites carcinoma-bearing mice

Breast cancer is a leading cause of death. Anticancer treatment such as gold nanoparticles (AuNP) seems highly promising in this regard. Therefore, this study aimed to assess the beneficial effect of doxorubicin (Dox) and polydatin (PD) AuNP in Ehrlich ascites carcinoma (EAC) and the ability of PD-AuNP to protect the heart from Dox's deteriorating effects. EAC was induced in mice. The mice were divided into nine groups: normal, EAC, PD: received PD (20 mg/kg), Dox: received Dox (2 mg/kg), PD-AuNPH: received 10 ppm AuNP of PD, PD-AuNPL: received 5 ppm AuNP of PD, Dox-AuNP: received Dox-AuNP, PD-Dox-AuNP: received PD-Dox-AuNP, AuNP: received AuNP. On the 21st day from tumor inoculation, the mice were sacrificed and tumor and heart tissues were removed. Tumor β-catenin/Cyclin D1 and p53 were assessed by immunohistochemistry. IL-6 was determined by enzyme-linked immunosorbent assay. PD-AuNP and Dox-AuNP showed a significant reduction in tumor volume and weight more than their free forms. Also, PD-AuNP and Dox-AuNP showed markedly less dense tumor cells. β-catenin and Cyclin D1 were markedly decreased and p53 was highly upregulated by PD-AuNP and Dox-AuNP. Moreover, PD-AuNP and Dox-AuNP have the ability to decrease IL-6 production. PD-AuNP protected the heart from Dox-induced severe degeneration. Therefore, PD-AuNP could be a tool to decelerate the progression of breast cancer.

Recent Advances in Nanotechnology with Nano-Phytochemicals: Molecular Mechanisms and Clinical Implications in Cancer Progression

Biocompatible nanoparticles (NPs) containing polymers, lipids (liposomes and micelles), dendrimers, ferritin, carbon nanotubes, quantum dots, ceramic, magnetic materials, and gold/silver have contributed to imaging diagnosis and targeted cancer therapy. However, only some NP drugs, including Doxil^® (liposome-encapsulated doxorubicin), Abraxane^® (albumin-bound paclitaxel), and Oncaspar^® (PEG-Asparaginase), have emerged on the pharmaceutical market to date. By contrast, several phytochemicals that were found to be effective in cultured cancer cells and animal studies have not shown significant efficacy in humans due to poor bioavailability and absorption, rapid clearance, resistance, and toxicity. Research to overcome these drawbacks by using phytochemical NPs remains in the early stages of clinical translation. Thus, in the current review, we discuss the progress in nanotechnology, research milestones, the molecular mechanisms of phytochemicals encapsulated in NPs, and clinical implications. Several challenges that must be overcome and future research perspectives are also described.

Co-encapsulation of gemcitabine and tocotrienols in nanovesicles enhanced efficacy in pancreatic cancer

Aim: To synthesize niosomes co-encapsulating gemcitabine (GEM) and tocotrienols, and physicochemically characterize and evaluate the antipancreatic effects of the nanoformulation on Panc 10.05, SW 1990, AsPC-1 and BxPC-3 cells. Materials & methods: Niosomes-entrapping GEM and tocotrienols composed of Span 60, cholesterol and D-α-tocopheryl polyethylene glycol 1000 succinate were produced by Handjani-Vila and film hydration methods. Results: The film hydration produced vesicles measuring 161.9 ± 0.5 nm, approximately 50% smaller in size than Handjani-Vila method, with maximum entrapment efficiencies of 20.07 ± 0.22% for GEM and 34.52 ± 0.10% for tocotrienols. In Panc 10.05 cells, GEM's antiproliferative effect was enhanced 2.78-fold in combination with tocotrienols. Niosomes produced a significant ninefold enhancement in cytotoxicity of the combination, supported by significantly higher cellular uptake of GEM in the cells. Conclusion: This study is a proof of concept on the synthesis of dual-drug niosomes and their efficacy on pancreatic cancer cells in vitro.

Pharmacology and Pharmacokinetics of Vitamin E: Nanoformulations to Enhance Bioavailability

Vitamin E belongs to the family of lipid-soluble vitamins and can be divided into two groups, tocopherols and tocotrienols, with four isomers (alpha, beta, gamma and delta). Although vitamin E is widely known as a potent antioxidant, studies have also revealed that vitamin E possesses anti-inflammatory properties. These crucial properties of vitamin E are beneficial in various aspects of health, especially in neuroprotection and cardiovascular, skin and bone health. However, the poor bioavailability of vitamin E, especially tocotrienols, remains a great limitation for clinical applications. Recently, nanoformulations that include nanovesicles, solid-lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, and polymeric nanoparticles have shown promising outcomes in improving the efficacy and bioavailability of vitamin E. This review focuses on the pharmacological properties and pharmacokinetics of vitamin E and current advances in vitamin E nanoformulations for future clinical applications. The limitations and future recommendations are also discussed in this review.

Vitamin E in Atopic Dermatitis: From Preclinical to Clinical Studies

BACKGROUND

Oxidative stress and inflammation are some of the proposed mechanisms involved in the pathogenesis of atopic dermatitis (AD). Current pharmacotherapeutic approaches are effective yet they are not without adverse effects. Vitamin E has great potential as an adjunctive treatment for AD owing to its antioxidant and anti-inflammatory bioactivities.

SUMMARY

This review article summarizes the current available evidence from cellular, animal and clinical studies on the relationship between vitamin E and AD. The future prospects of vitamin E are also discussed. Vitamin E in practice does not show any toxicity to humans within a range of reasonable dosage. Albeit rarely, vitamin E as a contact allergen should be considered. Collectively, this review envisaged vitamin E as an adjunctive treatment for AD patients. Future research on the distinct effects of different vitamin E isoforms as well as their delivery system in skin disorders is needed.

Beta-Tocotrienol Exhibits More Cytotoxic Effects than Gamma-Tocotrienol on Breast Cancer Cells by Promoting Apoptosis via a P53-Independent PI3-Kinase Dependent Pathway

Studies on tocotrienols have progressively revealed the benefits of these vitamin E isoforms on human health. Beta-tocotrienol (beta-T3) is known to be less available in nature compared to other vitamin E members, which may explain the restricted number of studies on beta-T3. In the present study, we aim to investigate the anti-proliferative effects and the pro-apoptotic mechanisms of beta-T3 on two human breast adenocarcinoma cell lines MDA-MB-231 and MCF7. To assess cell viability, both cell lines were incubated for 24 and 48 h, with different concentrations of beta-T3 and gamma-T3, the latter being a widely studied vitamin E isoform with potent anti-cancerous properties. Cell cycle progression and apoptosis induction upon treatment with various concentrations of the beta-T3 isoform were assessed. The effect of beta-T3 on the expression level of several apoptosis-related proteins p53, cytochrome C, cleaved-PARP-1, Bax, Bcl-2, and caspase-3, in addition to key cell survival proteins p-PI3K and p-GSK-3 α/β was determined using western blot analysis. Beta-tocotrienol exhibited a significantly more potent anti-proliferative effect than gamma-tocotrienol on both cell lines regardless of their hormonal receptor status. Beta-T3 induced a mild G1 arrest on both cell lines, and triggered a mitochondrial stress-mediated apoptotic response in MDA-MB-231 cells. Mechanistically, beta-T3′s anti-neoplastic activity involved the downregulation of phosphorylated PI3K and GSK-3 cell survival proteins. These findings suggest that vitamin E beta-T3 should be considered as a promising anti-cancer agent, more effective than gamma-T3 for treating human breast cancer and deserves to be further studied to investigate its effects in vitro and on other cancer types.

Liposome Delivery of Natural STAT3 Inhibitors for the Treatment of Cancer

In the tumor microenvironment, cytokines, growth factors, and oncogenes mediate constitutive activation of the signal transducer and activator of transcription 3 (STAT3) signaling pathway in both cancer cells and infiltrating immune cells. STAT3 activation in cancer cells drives tumorigenic changes that allow for increased survival, proliferation, and resistance to apoptosis. The modulation of immune cells is more complicated and conflicting. STAT3 signaling drives the myeloid cell phenotype towards an immune suppressive state, which mediates T cell inhibition. On the other hand, STAT3 signaling in T cells leads to proliferation and T cell activity required for an anti-tumor response. Targeted delivery of STAT3 inhibitors to cancer cells and myeloid cells could therefore improve therapeutic outcomes. Many compounds that inhibit the STAT3 pathways for cancer treatment include peptide drugs, small molecule inhibitors, and natural compounds. However, natural compounds that inhibit STAT3 are often hydrophobic, which reduces their bioavailability and leads to unfavorable pharmacokinetics. This review focuses specifically on liposome-encapsulated natural STAT3 inhibitors and their ability to target cancer cells and myeloid cells to reduce tumor growth and decrease STAT3-mediated immune suppression. Many of these liposome formulations have led to profound tumor reduction and examples of combination formulations have been shown to eliminate tumors through immune modulation.

H2O2-responsive nano-prodrug for podophyllotoxin delivery

The tumor microenvironment is different from that of normal tissue; therefore, the development of a prodrug that retains its efficacy in the tumor microenvironment can be useful in enhancing the anticancer properties of podophyllotoxin. An innovative podophyllotoxin prodrug (POD-PEG) was designed by linking podophyllotoxin to poly(ethylene glycol)(n) monomethacrylate with a H2O2-responsive oxalate ester bond. POD-PEG can self-assemble into stable nanoparticles (POD-PEG NPs). In vitro experiments demonstrated that the POD-PEG NPs can be activated by hydrogen peroxide resulting in podophyllotoxin release and are highly toxic against colon carcinoma CT26 cells. In vivo biodistribution studies demonstrate that PEGylated POD-PEG NPs are capable of prolonging blood circulation. Intravenous injection of POD-PEG NPs into CT26 tumor-bearing Balb/c mice resulted in a significantly enhanced therapeutic efficacy against tumors, with no significant systemic toxicity. Therefore, this H2O2-responsive prodrug delivery system exhibits good biosafety and provides a novel strategy for the development of drug delivery systems.

The synergism of Clinacanthus nutans Lindau extracts with gemcitabine: downregulation of anti-apoptotic markers in squamous pancreatic ductal adenocarcinoma

BACKGROUND

Clinacanthus nutans extracts have been consumed by the cancer patients with the hope that the extracts can kill cancers more effectively than conventional chemotherapies. Our previous study reported its anti-inflammatory effects were caused by inhibiting Toll-like Receptor-4 (TLR-4) activation. However, we are unsure of its anticancer effect, and its interaction with existing chemotherapy.

METHODS

We investigated the anti-proliferative efficacy of polar leaf extracts (LP), non-polar leaf extracts (LN), polar stem extract (SP) and non-polar stem extracts (SN) in human breast, colorectal, lung, endometrial, nasopharyngeal, and pancreatic cancer cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT assay. The most potent extracts was tested along with gemcitabine using our established drug combination analysis. The effect of the combinatory treatment in apoptosis were quantified using enzyme-linked immunosorbent assay (ELISA), Annexin V assay, antibody array and immunoblotting. Statistical significance was analysed using one-way analysis of variance (ANOVA) and post hoc Dunnett's test. A p-value of less than 0.05 (p < 0.05) was considered statistical significance.

RESULTS

All extracts tested were not able to induce potent anti-proliferative effects. However, it was found that pancreatic ductal adenocarcinoma, PDAC (AsPC1, BxPC3 and SW1990) were the cell lines most sensitive cell lines to SN extracts. This is the first report of C. nutans SN extracts acting in synergy with gemcitabine, the first line chemotherapy for pancreatic cancer, as compared to conventional monotherapy. In the presence of SN extracts, we can reduce the dose of gemcitabine 2.38-5.28 folds but still maintain the effects of gemcitabine in PDAC. SN extracts potentiated the killing of gemcitabine in PDAC by apoptosis. Bax was upregulated while bcl-2, cIAP-2, and XIAP levels were downregulated in SW1990 and BxPC3 cells treated with gemcitabine and SN extracts. The synergism was independent of TLR-4 expression in pancreatic cancer cells.

CONCLUSION

These results provide strong evidence of C. nutans extracts being inefficacious as monotherapy for cancer. Hence, it should not be used as a total substitution for any chemotherapy agents. However, SN extracts may synergise with gemcitabine in the anti-tumor mechanism.

Sustained delivery of a camptothecin prodrug - CZ48 by nanosuspensions with improved pharmacokinetics and enhanced anticancer activity

Background and aim: We have synthesized a novel lactone-stabilized camptothecin (CPT) analog named CZ48 and demonstrated its potent anticancer effects via bioconversion to the active CPT in earlier studies. Herein, we aimed to develop, optimize and characterize CZ48 nanosuspensions, for a sustained delivery of this drug in humans with an intravenous (i.v.) administration.

Methods and materials: A three-factor, five-level central composite design (CCD) was employed to establish the impacts of the critical influencing factors (concentrations (wt%) of CZ48, polysorbate 80 (Tween-80), and Pluronic^® F-108 (F-108)) on the responses (particle size and zeta potential). Based on the quantitative influencing factor–response relationships, two optimized CZ48 nanosuspensions of 197.22 ± 7.12 nm (NS-S) and 589.35 ± 23.27 nm (NS-L) were developed with the zeta potential values of –26.5 mV and –27.9 mV, respectively.

Results: CZ48 released from the nanosuspensions in a sustained manner in contrast to the rapid release from cosolvent in both PBS and human plasma. Moreover, NS-S exhibited more favored pharmacokinetic properties than NS-L, with a 31-fold prolonged elimination half-life of CPT, and a 2.4-fold enhanced CPT exposure over cosolvent. In efficacy study, NS-S exhibited significant tumor suppression and an improved survival rate with a higher tolerable dose, compared to CZ48 cosolvent.

Conclusion: We have successfully developed CZ48 nanosuspensions with significantly favorable pharmacokinetics and improved efficacy using CCD approach. The formulation offers potential merits as a preferred candidate for clinical trials with the prolonged CPT exposure, which is known to correlate with the clinical efficacy.

Therapeutic challenges and current immunomodulatory strategies in targeting the immunosuppressive pancreatic tumor microenvironment

BACKGROUND

Pancreatic cancer is one of the most lethal type of cancers, with an overall five-year survival rate of less than 5%. It is usually diagnosed at an advanced stage with limited therapeutic options. To date, no effective treatment options have demonstrated long-term benefits in advanced pancreatic cancer patients. Compared with other cancers, pancreatic cancer exhibits remarkable resistance to conventional therapy and possesses a highly immunosuppressive tumor microenvironment (TME).

MAIN BODY

In this review, we summarized the evidence and unique properties of TME in pancreatic cancer that may contribute to its resistance towards immunotherapies as well as strategies to overcome those barriers. We reviewed the current strategies and future perspectives of combination therapies that (1) promote T cell priming through tumor associated antigen presentation; (2) inhibit tumor immunosuppressive environment; and (3) break-down the desmoplastic barrier which improves tumor infiltrating lymphocytes entry into the TME.

CONCLUSIONS

It is imperative for clinicians and scientists to understand tumor immunology, identify novel biomarkers, and optimize the position of immunotherapy in therapeutic sequence, in order to improve pancreatic cancer clinical trial outcomes. Our collaborative efforts in targeting pancreatic TME will be the mainstay of achieving better clinical prognosis among pancreatic cancer patients. Ultimately, pancreatic cancer will be a treatable medical condition instead of a death sentence for a patient.

The Role of Tocotrienol in Preventing Male Osteoporosis-A Review of Current Evidence

Male osteoporosis is a significant but undetermined healthcare problem. Men suffer from a higher mortality rate post-fracture than women and they are marginalized in osteoporosis treatment. The current prophylactic agents for osteoporosis are limited. Functional food components such as tocotrienol may be an alternative option for osteoporosis prevention in men. This paper aims to review the current evidence regarding the skeletal effects of tocotrienol in animal models of male osteoporosis and its potential antiosteoporotic mechanism. The efficacy of tocotrienol of various sources (single isoform, palm and annatto vitamin E mixture) had been tested in animal models of bone loss induced by testosterone deficiency (orchidectomy and buserelin), metabolic syndrome, nicotine, alcoholism, and glucocorticoid. The treated animals showed improvements ranging from bone microstructural indices, histomorphometric indices, calcium content, and mechanical strength. The bone-sparing effects of tocotrienol may be exerted through its antioxidant, anti-inflammatory, and mevalonate-suppressive pathways. However, information pertaining to its mechanism of actions is superficial and warrants further studies. As a conclusion, tocotrienol could serve as a functional food component to prevent male osteoporosis, but its application requires validation from a clinical trial in men.