Amygdalin-folic acid-nanoparticles inhibit the proliferation of breast cancer and enhance the effect of radiotherapy through the modulation of tumor-promoting factors/ immunosuppressive modulators in vitro

Targeting the Enhanced Sensitivity of Radiotherapy in Cancer: Mechanisms, Applications, and Challenges

Cancer is a major public health, societal, and economic challenge worldwide. According to Global Cancer Statistics 2022, it is estimated that by 2050, there will be 35 million new cancer cases globally. Although patient survival rates have improved through various therapeutic approaches, including surgery, chemotherapy, and radiotherapy, treatment efficacy remains limited once tumor metastasis occurs. Among various cancer treatment strategies, radiotherapy plays a crucial role. Along with surgery and chemotherapy, radiotherapy is a cost-effective single-modality treatment, accounting for approximately 5% of total cancer care costs. The use of radiosensitizing agents such as histone deacetylase inhibitors, 2-deoxy-d-glucose, enterolactone, and squalene epoxidase can enhance radiotherapy effectiveness. Recent radiosensitization methods involve physical stimuli and chemical radiosensitizers. However, improving their efficacy, durability, and overcoming radioresistance remain significant challenges. This review first introduces current applications of radiotherapy in cancer treatment, the molecular mechanisms underlying its anticancer effects, and its side effects. Second, it discusses the main types of radiosensitizers, their latest applications, and recent challenges in cancer treatment. Finally, it emphasizes on clinical trials of radiosensitizing agents and explores potential biomarkers for radiotherapy response in cancer. Multifunctional nanoparticles have shown greater clinical applicability than single-functional nanoparticles. Future research will focus on enhancing the drug-carrying capacity of nanomaterials to further improve radiotherapy outcomes.

Unraveling the breast cancer tumor microenvironment: crucial factors influencing natural killer cell function and therapeutic strategies

Natural killer (NK) cells have emerged as a novel and effective treatment for breast cancer. Nevertheless, the breast cancer tumor microenvironment (TME) manifests multiple immunosuppressive mechanisms, impeding the proper execution of NK cell functions. This review summarizes recent research on the influence of the TME on the functionality of NK cells in breast cancer. It delves into the effects of the internal environment of the TME on NK cells and elucidates the roles of diverse stromal components, immune cells, and signaling molecules in regulating NK cell activity within the TME. It also summarizes therapeutic strategies based on small-molecule inhibitors, antibody therapies, and natural products, as well as the progress of research in preclinical and clinical trials. By enhancing our understanding of the immunosuppressive TME and formulating strategies to counteract its effects, we could fully harness the therapeutic promise of NK cells in breast cancer treatment.

Radiosensitizing properties of dual-functionalized carbon nanostructures loaded with temozolomide

In the present study, temozolomide (TMZ), a drug used for the treatment of anaplastic astrocytoma and glioblastoma multiforme (GBM), was incorporated into multiwalled carbon nanotubes (MWCNTs) and a MWCNTs-graphene (MWCNTs-G) hybrid compound, covalently functionalized with polyethylene glycol (PEG) 6000 and folic acid (FA), with an aim to prepare nanocarriers with the potential to prolong the drug circulation time, cross the blood-brain-tumor barrier (BBTB), and provide targeted and controlled drug release in the brain tumor cells. Cytotoxicity and effects on cell membrane integrity of the blank and TMZ-loaded dual-functionalized carbon nanostructures (CNs) were evaluated in vitro on a GBM cell line (U87MG), as well as their radiosensitizing properties after exposure of the pre-treated GBM cells to gamma radiation with a standard clinical dose for patients with GBM. All prepared formulations underwent biopharmaceutical and physicochemical characterization, including the formulations exposed to irradiation under the same conditions. For physicochemical characterization of the formulations, different techniques were used by which successful functionalization of the CNs and TMZ loading were confirmed and visualized; no significant changes in the structure of the CNs and TMZ after irradiation were observed. With single and dual functionalization, formulations with relatively high TMZ loading efficiency and drug content were prepared. They exhibited homogeneous particle size distributions and mean particle sizes and surface charges suitable for crossing the BBTB and targeting brain cancer cells. A biphasic drug release profile was observed for all functionalized TMZ-loaded formulations in simulated in vivo conditions, with a sustained release pointing to the potential for controlled release of TMZ in brain tumor cells. The formulations of the hybrid CN MWCNTs-G compared to the corresponding MWCNTs were characterized by a similar or slightly higher TMZ content, larger particle size, similar surface charge, and slightly faster TMZ release, which can be attributed to the planar structure of graphene that promotes TMZ binding to the surface on a larger scale. For the irradiated CNs, lower values for particle size, more positive values for surface charge, and accelerated TMZ release were observed, which could be explained by changes in the physicochemical characteristics of the prepared formulations upon irradiation. Significant concentration-dependent toxicity was observed for blank dual-functionalized CNs, being higher for MWCNTs-G-PEG6000-FA compared to MWCNTs-PEG6000-FA at the same formulation concentrations. With incorporation of TMZ into the functionalized CNs, the cell viability additionally decreased, maintaining the trend for higher cytotoxicity of the hybrid CN. Additional decrease in the viability of cells was observed when GBM cells pre-treated with the corresponding CNs were exposed to irradiation, which could be ascribed to changes in size, surface charge, and release kinetics of TMZ and to irradiation-induced changes in the microenvironment and cell membranes that promote uptake of a larger volume of carriers in the GBM cells. The higher cytotoxicity observed in the hybrid carrier formulations could most likely be attributed to the length of the hybrid carrier and the higher proportion of planar surface, which promotes more intense contact with the cells and rupture of cell membranes. Overall, the findings demonstrate the radiosensitizing properties of not only TMZ but also of CNs and point to a clinical benefit from combined treatment with carbon nanocarriers of TMZ and radiotherapy in GBM.

Ginkgetin enhances breast cancer radiotherapy sensitization by suppressing NRF2-HO-1 axis activity

Breast cancer (BC) is a critical threat to women's lives. Radiotherapy (RT) is a pivotal treatment modality for BC, but the failure of RT due to radioresistance is still not well facilitated. Ginkgetin (GK) has a potent anti-tumor activity intimately associated with ferroptosis. This study applied in vitro and in vivo experimental models to ascertain the GK mechanism of action on BC radioresistance. The outcomes reported that GK could inhibit BC cell growth and increase apoptosis. In addition, when BC cells generated radioresistance, GK promoted ferroptosis of radioresistant BC cells by mitigating NRF2 expression, suppressing HO-1 and NQO1 expression, increasing the intracellular content of reactive oxygen species (ROS) and ferrous ions, accelerating the glutathione (GSH) depletion, and decreasing GPX4 expression. Notably, GK can damage intracellular mitochondria and cause a substantial increase in ferrous ions in BC cells. Therefore, GK shows immense potential for enhancing breast cancer radiotherapy sensitivity, which may provide pivotal evidence for subsequent RT sensitization.

Amygdalin in antineoplastic medicine and the relevance of nanotechnology

Amygdalin is a plant-based cyanogenic glycoside that has been the subject of both scientific interest and controversy for decades. Traditionally used in alternative medicine for its diverse biological activities, including anticancer, where amygdalin has been explored in complementary therapy. However, clinical utilization of amygdalin remains contentious due to concerns about its safety, primarily the release of hydrogen cyanide during its metabolism. Advancements in nanotechnology provides scope for the safe and targeted of amygdalin with improved bioavailability and targeted delivery of amygdalin, thereby, potentially eliminating the toxic effects. This review offers an update on the current research status surrounding amygdalin, with a focus on its molecular mechanisms of action, biological activities, and potential therapeutic applications. It also critically examines the challenges tied to its clinical use, particularly the safety concerns stemming from cyanide toxicity. Finally, the potential of nanotechnology in addressing cytotoxicity constraints is highlighted.

Recent Trends in Nanoparticulate Delivery System for Amygdalin as Potential Therapeutic Herbal Bioactive Agent for Cancer Treatment

Cancer is the deadliest and most serious health problem. The mortality rate of cancer patients has increased significantly worldwide in recent years. There are several treatments available, but these treatments have many limitations, such as non-specific targeting, toxicity, bioavailability, solubility, permeability problems, serious side effects, and a higher dose. Many people prefer phytomedicine because it has fewer side effects. However, amygdalin is a naturally occurring phytoconstituent. It has many harmful effects due to the cyanide group present in the chemical structure. Many scientists and researchers have given their thoughts associated with amygdalin and its toxicities. However, there is a need for a more advanced, effective, and newer delivery system with reduced toxicity effects of amygdalin. Nanotechnology has become a more refined and emerging medical approach, offering innovative research areas to treat cancer. This review focuses on the use of amygdaline as herbal medicine encapsulating into several nanoparticulate delivery systems such as silver nanoparticles, graphene oxide nanoparticles, gold nanoparticles, nanofibers, nanocomposites, niosomes, and magnetic nanoparticles in the treatment of cancer. In addition, this article provides information on amygdalin structure and physical properties, pharmacokinetics, toxicity, and challenges with amygdalin.

The immunomodulatory effects of vitamins in cancer

Nutrition may affect animal health due to the strong link between them. Also, diets improve the healing process in various disease states. Cancer is a disease, where the harmful consequences of tumors severely impair the body. The information regarding the evolution of this disease is extrapolated from human to animal because there are few specific studies regarding nutritional needs in animals with cancer. Thus, this paper aims to review the literature regarding the immunomodulatory effects of vitamins in mammal cancer. An adequate understanding of the metabolism and requirements of nutrients for mammals is essential to ensuring their optimal growth, development, and health, regardless of their food sources. According to these: 1) Some species are highly dependent on vitamin D from food, so special attention must be paid to this aspect. Calcitriol/VDR signaling can activate pro-apoptotic proteins and suppress anti-apoptotic ones. 2) Nitric oxide (NO) production is modulated by vitamin E through inhibiting transcription nuclear factor kappa B (NF-κB) activation. 3) Thiamine supplementation could be responsible for the stimulation of tumor cell proliferation, survival, and resistance to chemotherapy. 4) Also, it was found that the treatment with NO-Cbl in dogs is a viable anti-cancer therapy that capitalizes on the tumor-specific properties of the vitamin B12 receptor. Therefore, diets should contain the appropriate class of compounds in adequate proportions. Also, the limitations of this paper are that some vitamins are intensively studied and at the same time regarding others, there is a lack of information, especially in animals. Therefore, some subsections are longer and more heavily debated than others.

Biocompatibility and radiosensitivity of a fiber optical-based dosimeter: biological applications

This study introduces a cutting-edge fiber-optic dosimetry (FOD) sensor designed for measuring radiation in biological settings. The accuracy and precision of dosimeters for small animals, particularly prolonged exposure to nonuniform radiation fields, are always challenging. A state-of-the-art in-vivo dosimeter utilizing glass-encapsulated Thermoluminescence cylindrical detector (TLD) was introduced. The FODs are implanted into the rat during a prolonged irradiation scenario involving 137Cs where the rat has the freedom to move within a heterogeneous radiation domain. The implantation surgery was verified with X-ray computed tomography (CT) in addition to biochemical and pathological tests to assess the biocompatibility of FOD in vivo. A versatile FOD is designed for industrial and medical fields, which demand accurate and resilient radiation dosimeters. The dose measurements are associated with precise two-dimensional (2D) radiation distribution imaging. Three cylindrical FODs and three standards TLD_100 for each rat were tested. The measurements of peak irradiation before and after exposure reveal greater stability and superior sensitivity when compared to standard thermo-luminescence detectors in an in-vivo animal test. To the best of our knowledge, FOD testing on live animals is presented for the first time in this paper. Regarding the safety and biocompatibility of FOD, no morphological signs with any kind of inflammation or sensitivity toward the FOD material have been remarked. Moreover, with the current FOD, there is no oedema between the epidermal, dermal, and subdermal sections at the site of implantation. The results also show the stable levels of white blood cells (lymphocytes, granulocytes, MID) as blood inflammatory markers before surgery and at the time of extraction of the implanted dosimeters, thus confirming the biocompatibility for each optical fiber cylinder dosimeter. As a result, the new dosimeters have excellent biocompatibility in living tissues and have 100% accurate reusability intensity of the delivered radiation doses compared to TLD_100 which demonstrated a 45% reduction in its intensity accuracy.

Armeniacae semen amarum: a review on its botany, phytochemistry, pharmacology, clinical application, toxicology and pharmacokinetics

Armeniacae semen amarum-seeds of Prunus armeniaca L. (Rosaceae) (ASA), also known as Kuxingren in Chinese, is a traditional Chinese herbal drug commonly used for lung disease and intestinal disorders. It has long been used to treat coughs and asthma, as well as to lubricate the colon and reduce constipation. ASA refers to the dried ripe seed of diverse species of Rosaceae and contains a variety of phytochemical components, including glycosides, organic acids, amino acids, flavonoids, terpenes, phytosterols, phenylpropanoids, and other components. Extensive data shows that ASA exhibits various pharmacological activities, such as anticancer activity, anti-oxidation, antimicrobial activity, anti-inflammation, protection of cardiovascular, neural, respiratory and digestive systems, antidiabetic effects, and protection of the liver and kidney, and other activities. In clinical practice, ASA can be used as a single drug or in combination with other traditional Chinese medicines, forming ASA-containing formulas, to treat various afflictions. However, it is important to consider the potential adverse reactions and pharmacokinetic properties of ASA during its clinical use. Overall, with various bioactive components, diversified pharmacological actions and potent efficacies, ASA is a promising drug that merits in-depth study on its functional mechanisms to facilitate its clinical application.

Amygdalin as a Promising Anticancer Agent: Molecular Mechanisms and Future Perspectives for the Development of New Nanoformulations for Its Delivery

Cancer rates are increasing, and cancer is one of the main causes of death worldwide. Amygdalin, also known as vitamin B17 (and laetrile, a synthetic compound), is a cyanogenic glycoside compound that is mainly found in the kernels and pulps of fruits. This compound has been proposed for decades as a promising naturally occurring substance which may provide anticancer effects. This is a comprehensive review which critically summarizes and scrutinizes the available studies exploring the anticancer effect of amygdalin, highlighting its potential anticancer molecular mechanisms as well as the need for a nontoxic formulation of this substance. In-depth research was performed using the most accurate scientific databases, e.g., PubMed, Cochrane, Embase, Medline, Scopus, and Web of Science, applying effective, characteristic, and relevant keywords. There are several pieces of evidence to support the idea that amygdalin can exert anticancer effects against lung, breast, prostate, colorectal, cervical, and gastrointestinal cancers. Amygdalin has been reported to induce apoptosis of cancer cells, inhibiting cancer cells' proliferation and slowing down tumor metastatic spread. However, only a few studies have been performed in in vivo animal models, while clinical studies remain even more scarce. The current evidence cannot support a recommendation of the use of nutritional supplements with amygdalin due to its cyano-moiety which exerts adverse side effects. Preliminary data have shown that the use of nanoparticles may be a promising alternative to enhance the anticancer effects of amygdalin while simultaneously reducing its adverse side effects. Amygdalin seems to be a promising naturally occurring agent against cancer disease development and progression. However, there is a strong demand for in vivo animal studies as well as human clinical studies to explore the potential prevention and/or treatment efficiency of amygdalin against cancer. Moreover, amygdalin could be used as a lead compound by effectively applying recent developments in drug discovery processes.