The effect of environmental stressors on the anticancer potential of Amaranthus hypochondriacus aqueous extracts and fractions.

Some Amaranthus species have been shown to have pharmacological properties such as activity against cancer, and it is also used as a traditional herbal medicine in many rural parts of the world. The (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide assay was used as a screening tool to determine the approximate cell viability inhibitory concentrations of methanol and aqueous crude extracts of Amaranthus spp. The extracts were screened using small-cell lung cancer (H69V), hepatocellular carcinoma (HepG2/C3A) and non-cancerous kidney cells (Vero) cell lines. Viability was assessed following exposure to a series of concentrations of each extract and A. hypochondriacus showed cytotoxicity of 70.55 µg/mL against H69V with a Si index of 1.8. The fractionated aqueous extract of 40 °C-treated A. hypochondriacus under well-watered conditions had a higher viability inhibition on H69V and Vero cell lines compared to the A. caudatus, A. cruentus and A. spinosus crude extracts. In conclusion, A. hypochondriacus could serve as a potential source of anticancer phytoconstituents for drug development.

A Novel NCI-H69AR Drug-Resistant Small-Cell Lung Cancer Mini-Tumor Model for Anti-Cancer Treatment Screening.

Small-cell lung cancer is a fast-growing carcinoma with a poor prognosis and a high level of relapse due to multi-drug resistance (MDR). Genetic mutations that lead to the overexpression of efflux transporter proteins can contribute to MDR. In vitro cancer models play a tremendous role in chemotherapy development and the screening of possible anti-cancer molecules. Low-cost and simple in vitro models are normally used. Traditional two-dimensional (2D) models have numerous shortcomings when considering the physiological resemblance of an in vivo setting. Three-dimensional (3D) models aim to bridge the gap between conventional 2D models and the in vivo setting. Some of the advantages of functional 3D spheroids include better representation of the in vivo physiology and tumor characteristics when compared to traditional 2D cultures. During this study, an NCI-H69AR drug-resistant mini-tumor model (MRP1 hyperexpressive) was developed by making use of a rotating clinostat bioreactor system (ClinoStar®; CelVivo ApS, Odense, Denmark). Spheroid growth and viability were assessed over a 25-day period to determine the ideal experimental period with mature and metabolically stable constructs. The applicability of this model for anti-cancer research was evaluated through treatment with irinotecan, paclitaxel and cisplatin for 96 h, followed by a 96 h recovery period. Parameters measured included planar surface area measurements, estimated glucose consumption, soluble protein content, intracellular adenosine triphosphate levels, extracellular adenylate kinase levels, histology and efflux transporter gene expression. The established functional spheroid model proved viable and stable during the treatment period, with retained relative hyperexpression of the MRP1 efflux transporter gene but increased expression of the P-gp transporter gene compared to the cells cultured in 2D. As expected, treatment with the abovementioned anti-cancer drugs at clinical doses (100 mg/m2 irinotecan, 80 mg/m2 paclitaxel and 75 mg/m2 cisplatin) had minimal impact on the drug-resistant mini-tumors, and the functional spheroid models were able to recover following the removal of treatment.

Influence of Drought and Heat Stress on Mineral Content, Antioxidant Activity and Bioactive Compound Accumulation in Four African Amaranthus Species.

Drought and heat stress is known to influence the accumulation of mineral content, antioxidant activity, phenolics, flavonoids and other bioactive compounds in many tolerant leafy vegetables. Amaranthus plants can tolerate adverse weather conditions, especially drought and heat. Therefore, evaluating the influence of drought and heat stress on commercially and medically important crop species like Amaranthus is important to grow the crop for optimal nutritional and medicinal properties. This study investigated the influence of drought and heat stress and a combination of both on the accumulation of phenolic and flavonoid compounds and the antioxidant capacity of African Amaranthus caudatus, A. hypochondriacus, A. cruentus and A. spinosus. Phenolic and flavonoid compounds were extracted with methanol and aqueous solvents and were quantified using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Caffeic acid was the main phenolic compound identified in aqueous extracts of A. caudatus and A. hypochondriacus. Rutin was the most abundant flavonoid compound in all the Amaranthus species tested, with the highest concentration found in A. caudatus. The results suggest a strong positive, but species and compound-specific effect of drought and heat stress on bioactive compounds accumulation. We concluded that heat stress at 40 °C under well-watered conditions and combined drought and heat stress (at 30 °C and 35 °C) appeared to induce the accumulation of caffeic acid and rutin. Hence, cultivation of these species in semi-arid and arid areas is feasible.

A novel NCI-H69V small cell lung cancer functional mini-tumor model for future treatment screening applications.

Small cell lung cancer (SCLC) is aggressive and despite multiple clinical trials, its standard of care is unchanged for the past three decades. In vitro cancer models are crucial in chemotherapy development, and three-dimensional (3D) models aim to bridge the gap between two-dimensional (2D) flat cultures and in vivo testing. Functional 3D spheroids can better represent the in vivo situation and tumor characteristics than 2D models. An NCI-H69V SCLC mini-tumor model was developed in a clinostat-based rotating bioreactor system. Spheroid growth and viability were characterized for 30 days, and the ideal experimental window with mature and metabolically stable spheroids was determined. Application of the model for anticancer treatment screening was validated with the standard chemotherapeutic drug irinotecan, for an exposure period of 72 h. The following parameters were measured: soluble protein content, planar surface area measurements, intracellular adenosine triphosphate and extracellular adenylate kinase levels, and glucose consumption. Histological morphology of the spheroids was observed. The established model proved viable and stable, while treatment with irinotecan caused a decrease in cell growth, viability, and glucose consumption demonstrating reactivity of the model to chemotherapy. Therefore, this NCI-H69V SCLC functional spheroid model could be used for future anticancer compound screening.

The interactive effects of drought and heat stress on photosynthetic efficiency and biochemical defense mechanisms of Amaranthus species.

Drought and heat stress are major abiotic stress factors that limit photosynthesis and other related metabolic processes that hamper plant growth and productivity. Identifying plants that can tolerate abiotic stress conditions is essential for sustainable agriculture. Amaranthus plants can tolerate adverse weather conditions, especially drought and heat, and their leaves and grain are highly nutritious. Because of these traits, amaranth has been identified as a possible crop to be grown in marginal crop production systems. Therefore, this study investigated the photochemical and biochemical responses of Amaranthus caudatus, Amaranthus hypochondriacus, Amaranthus cruentus, and Amaranthus spinosus to drought stress, heat shock treatments, and a combination of both. After the six-leaf stage in a greenhouse, plants were subjected to drought stress, heat shock treatments, and a combination of both. Chlorophyll a fluorescence was used to evaluate the photochemical responses of photosystem II to heat shock while subjected to drought stress. It was found that heat shock and a combination of drought and heat shock damages photosystem II, but the level of damage varies considerably between the species. We concluded that A. cruentus and A. spinosus are more heat and drought-tolerant than Amaranthus caudatus and Amaranthus hypochondriacus.

Molecular mechanisms and associated cell signalling pathways underlying the anticancer properties of phytochemical compounds from Aloe species (Review).

Naturally occurring components from various species of Aloe have been used as traditional folk medicine since the ancient times. Over the last few decades, the therapeutic effects of extracts and phytochemical compounds obtained from Aloe vera have been proven in preclinical and clinical studies. Recently, compounds from other Aloe species apart from Aloe vera have been investigated for the treatment of different diseases, with a particular focus on cancer. In the present review, the effects of phytochemical compounds obtained from different Aloe species are discussed, with a specific focus on the effects on cell signalling in cancer and normal cells, and their selectivity and efficacy. This information will be useful for the application of Aloe-derived compounds as therapeutic agents, either alone or in combination with other standard drugs for cancer treatment.

Clinostat 3D Cell Culture: Protocols for the Preparation and Functional Analysis of Highly Reproducible, Large, Uniform Spheroids and Organoids.

Growing cells as 3D structures need not be difficult. Often, it is not necessary to change cell type, additives or growth media used. All that needs to be changed is the geometry: cells (whether primary, induced pluripotent, transformed or immortal) simply have to be grown in conditions that promote cell-cell adhesion while allowing gas, nutrient, signal, and metabolite exchange. Downstream analysis can become more complicated because many assays (like phase contrast microscopy) cannot be used, but their replacements have been in use for many years. Most importantly, there is a huge gain in value in obtaining data that is more representative of the organism in vivo. It is the goal of the protocols presented here to make the transition to a new dimension as painless as possible. Grown optimally, most biopsy derived organoids will retain patient phenotypes, while cell (both stem cell, induced or otherwise or immortalized) derived organoids or spheroids will recover tissue functionality.

Anticancer Potential of Sutherlandia frutescens and Xysmalobium undulatum in LS180 Colorectal Cancer Mini-Tumors.

Colorectal cancer remains to be one of the leading causes of death worldwide, with millions of patients diagnosed each year. Although chemotherapeutic drugs are routinely used to treat cancer, these treatments have severe side effects. As a result, the use of herbal medicines has gained increasing popularity as a treatment for cancer. In this study, two South African medicinal plants widely used to treat various diseases, Sutherlandia frutescens and Xysmalobium undulatum, were evaluated for potential activity against colorectal cancer. This potential activity for the treatment of colorectal cancer was assessed relative to the known chemotherapeutic drug, paclitaxel. The cytotoxic activity was considered in an advanced three-dimensional (3D) sodium alginate encapsulated LS180 colorectal cancer functional spheroid model, cultured in clinostat-based rotating bioreactors. The LS180 cell mini-tumors were treated for 96 h with two concentrations of each of the crude aqueous extracts or paclitaxel. S. frutescens extract markedly decreased the soluble protein content, while decreasing ATP and AK per protein content to below detectable limits after only 24 h exposure. X. undulatum extract also decreased the soluble protein content, cell viability, and glucose consumption. The results suggested that the two phytomedicines have potential to become a source of new treatments against colorectal cancer.

Characterization of an Alginate Encapsulated LS180 Spheroid Model for Anti-colorectal Cancer Compound Screening.

Colorectal cancer is one of the leading causes of cancer-related deaths. A main problem for its treatment is resistance to chemotherapy, requiring the development of new drugs. The success rate of new candidate cancer drugs in clinical trials remains dismal. Three-dimensional (3D) cell culture models have been proposed to bridge the current gap between in vitro chemotherapeutic studies and the human in vivo, due to shortcomings in the physiological relevance of the commonly used two-dimensional cell culture models. In this study, LS180 colorectal cancer cells were cultured as 3D sodium alginate encapsulated spheroids in clinostat bioreactors. Growth and viability were evaluated for 20 days to determine the ideal experimental window. The 3- (4,5- dimethylthiazol- 2- yl)-2,5-diphenyltetrazolium bromide assay was then used to establish half maximal inhibitory concentrations for the standard chemotherapeutic drug, paclitaxel. This concentration was used to further evaluate the established 3D model. During model characterization and evaluation soluble protein content, intracellular adenosine triphosphate levels, extracellular adenylate kinase, glucose consumption, and P-glycoprotein (P-gp) gene expression were measured. Use of the model for chemotherapeutic treatment screening was evaluated using two concentrations of paclitaxel, and treatment continued for 96 h. Paclitaxel caused a decrease in cell growth, viability, and glucose consumption in the model. Furthermore, relative expression of P-gp increased compared to the untreated control group. This is a typical resistance-producing change, seen in vivo and known to be a result of paclitaxel treatment. It was concluded that the LS180 sodium alginate encapsulated spheroid model could be used for testing new chemotherapeutic compounds for colorectal cancer.

Treatment of Skin Disorders with Aloe Materials.

The skin is the largest organ and functions as a barrier to protect the underlying tissues against the elements and pathogens, while also fulfilling many physiological roles and biochemical functions such as preventing excessive water loss. Skin disorders vary greatly in terms of origin, severity, symptoms and affect persons of all ages. Many plants have been used for medicinal purposes since ancient times including the treatment of skin disorders and diseases. Aloe represents one of the earliest medicinal plant species mentioned in antique scriptures and even in rock art dating back thousands of years. Different Aloe species and materials have been used in the prevention and treatment of skin related disorders. Aloe vera is the most commonly used Aloe species for medicinal purposes. Some of the most prominent skin related applications and disorders that Aloe materials have been investigated for are discussed in this paper, which include cosmetic, radiation, cancer, wound and antimicrobial applications. Both in vitro and in vivo studies are included in the discussions of this paper and comprehensive summaries of all these studies are given in tables in each section. Although some contradictory results were obtained among studies, certain Aloe materials have shown excellent efficacy and exhibited potential for the treatment of skin related disorders and cosmetic applications.

Models used to screen for the treatment of multidrug resistant cancer facilitated by transporter-based efflux.

PURPOSE: Efflux transporters of the adenosine triphosphate-binding cassette (ABC)-superfamily play an important role in the development of multidrug resistance (multidrug resistant; MDR) in cancer. The overexpression of these transporters can directly contribute to the failure of chemotherapeutic drugs. Several in vitro and in vivo models exist to screen for the efficacy of chemotherapeutic drugs against MDR cancer, specifically facilitated by efflux transporters. RESULTS: This article reviews a range of efflux transporter-based MDR models used to test the efficacy of compounds to overcome MDR in cancer. These models are classified as either in vitro or in vivo and are further categorised as the most basic, conventional models or more complex and advanced systems. Each model's origin, advantages and limitations, as well as specific efflux transporter-based MDR applications are discussed. Accordingly, future modifications to existing models or new research approaches are suggested to develop prototypes that closely resemble the true nature of multidrug resistant cancer in the human body. CONCLUSIONS: It is evident from this review that a combination of both in vitro and in vivo preclinical models can provide a better understanding of cancer itself, than using a single model only. However, there is still a clear lack of progression of these models from basic research to high-throughput clinical practice.

A sub-chronic Xysmalobium undulatum hepatotoxicity investigation in HepG2/C3A spheroid cultures compared to an in vivo model.

ETHNOPHARMACOLOGY RELEVANCE: Traditional herbal medicines are utilized by 27 million South Africans. Xysmalobium undulatum (Uzara) is one of the most widely used traditional medicinal plants in Southern Africa. A false belief in the safety of herbal medicine may result in liver injury. Herb-induced liver injury (HILI) range from asymptomatic elevation of liver enzymes, to cirrhosis and in certain instances even acute liver failure. Various in vitro and in vivo models are available for the pre-clinical assessment of drug and herbal hepatotoxicity. However, more reliable and readily available in vitro models are needed, which are capable of bridging the gap between existing models and real human exposure. Three-dimensional (3D) spheroid cultures offer higher physiological relevance, overcoming many of the shortcomings of traditional two-dimensional cell cultures. AIMS OF THIS STUDY: This study investigated the hepatotoxic and anti-prolific effects of the crude X. undulatum aqueous extract during a sub-chronic study (21 days), in both a 3D HepG2/C3A spheroid model and the Sprague Dawley rat model. METHODS: HepG2/C3A spheroids were treated with a known hepatotoxin, valproic acid, and crude X. undulatum aqueous extract for 21 days with continuous evaluation of cell viability and proliferation. This was done by evaluating cell spheroid growth, intracellular adenosine triphosphate (ATP) levels and extracellular adenylate kinase (AK). Sprague Dawley rats were treated with the same compounds over 21 days, with evaluation of in vivo toxicity effects on serum chemistry. RESULTS: The results from the in vitro study clearly indicated hepatotoxic effects and possible liver damage following treatment with valproic acid, with associated growth inhibition, loss of cell viability and increased cytotoxicity as indicated by reduced intracellular ATP levels and increased AK levels. These results were supported by the increased in vivo levels of AST, ALT and LDH following treatment of the Sprague Dawley rats with valproic acid, indicative of hepatic cellular damage that may result in hepatotoxicity. The in vitro 3D spheroid model was also able to predict the potential concentration dependant hepatotoxicity of the crude X. undulatum aqueous extract. Similarly, the results obtained from the in vivo Sprague Dawley model indicated moderate hepatotoxic potential. CONCLUSION: The data from both the 3D spheroid model and the Sprague Dawley model were able to indicate the potential concentration dependant hepatotoxicity of the crude X. undulatum aqueous extract. The results obtained from this study also confirmed the ability of the 3D spheroid model to effectively and reliably predict the long-term outcomes of possible hepatotoxicity.

Drug Bioavailability Enhancing Agents of Natural Origin (Bioenhancers) that Modulate Drug Membrane Permeation and Pre-Systemic Metabolism.

Many new chemical entities are discovered with high therapeutic potential, however, many of these compounds exhibit unfavorable pharmacokinetic properties due to poor solubility and/or poor membrane permeation characteristics. The latter is mainly due to the lipid-like barrier imposed by epithelial mucosal layers, which have to be crossed by drug molecules in order to exert a therapeutic effect. Another barrier is the pre-systemic metabolic degradation of drug molecules, mainly by cytochrome P450 enzymes located in the intestinal enterocytes and liver hepatocytes. Although the nasal, buccal and pulmonary routes of administration avoid the first-pass effect, they are still dependent on absorption of drug molecules across the mucosal surfaces to achieve systemic drug delivery. Bioenhancers (drug absorption enhancers of natural origin) have been identified that can increase the quantity of unchanged drug that appears in the systemic blood circulation by means of modulating membrane permeation and/or pre-systemic metabolism. The aim of this paper is to provide an overview of natural bioenhancers and their main mechanisms of action for the nasal, buccal, pulmonary and oral routes of drug administration. Poorly bioavailable drugs such as large, hydrophilic therapeutics are often administered by injections. Bioenhancers may potentially be used to benefit patients by making systemic delivery of these poorly bioavailable drugs possible via alternative routes of administration (i.e., oral, nasal, buccal or pulmonary routes of administration) and may also reduce dosages of small molecular drugs and thereby reduce treatment costs.

Toxicity and anti-prolific properties of Xysmalobium undulatum water extract during short-term exposure to two-dimensional and three-dimensional spheroid cell cultures.

Xysmalobium undulatum (Uzara) is one of the most widely used indigenous traditional herbal remedies in Southern Africa. Commercially available Uzara plant material was used to prepare a crude aqueous extract, of which the toxicity potential was investigated in the hepatic HepG2/C3A cell line in both traditional two-dimensional (2D) and rotating three-dimensional (3D) spheroid cell cultures. These cultures were treated over a period of 4 days at concentrations of 200, 350, 500, and 750 mg/kg plant extract to protein content. Basic physiological parameters of the cell cultures were measured during exposure, including cell proliferation, glucose uptake, intracellular adenosine triphosphate levels, and adenylate kinase release. The results indicated that all physiological parameters monitored were affected in a dose dependent manner, with the highest concentration of Uzara crude water extract (750 mg/kg) resulting in toxicity. Anti-proliferating effects of Uzara crude water extract were observed in both the 2D and 3D cell cultures, with the most pronounced effects at concentrations of 350, 500, and 750 mg/kg. Discrepancies between results obtained from the 2D and 3D cell culture models may be attributed to the type of repair system that is initiated upon exposure, depending on where cells are within the cell cycle. DNA repair systems differ in cells within the G1 phase and non-diving cells, (i.e. cells found predominantly in in vitro 3D and the in vivo situation).

Absorptive and Secretory Transport of Selected Artemisinin Derivatives Across Caco-2 Cell Monolayers.

BACKGROUND: Malaria continues to be a major health concern and affects more than 200 million people a year. Drugs currently used for treatment of malaria are increasingly rendered ineffectual by the ongoing emergence of parasite resistance. For any new drugs, however, knowledge of their membrane permeability is an essential pre-requisite for eventual use. Treatment failure and emergence of resistance can occur as a result of reduced availability of the drug at the desired site of action. Cellbased permeability assays such as Caco-2 cell monolayers serve as a model for predicting drug absorption and efflux, and provide an estimate of drug bioavailability. OBJECTIVE: Here we have studied the bi-directional transport of new anti-malarial compounds, artemisone and artemiside, as well as reference compounds, namely the known anti-malarial drug artemether, and caffeine and atenolol. METHODS: The Caco-2 cell monolayer model was used to assess the membrane permeation properties of these compounds, and to identify if they are subject to P-gp associated efflux, in the presence and absence of verapamil. The effect of piperine on the transport of the compounds that were identified to be P-gp substrates was also assessed. Samples withdrawn from the acceptor chambers at pre-determined time intervals were analysed by means of high-performance liquid chromatography (HPLC). RESULTS: Transport results in terms of the absorptive direction revealed that artemisone and artemether had low absorption rates relative to the reference compounds. It was further demonstrated that artemisone is slightly effluxed, and although both artemether and artemiside were susceptible to P-gp mediated efflux, it appears that other efflux proteins may also be involved. CONCLUSION: The low permeability of anti-malarial drugs must be borne in mind during development of effective dosage regimens of new drugs.

Recent advances in three-dimensional cell culturing to assess liver function and dysfunction: from a drug biotransformation and toxicity perspective.

The liver is a vital organ fulfilling a central role in over 500 major metabolic functions, including serving as the most essential site for drug biotransformation. Dysfunction of the drug biotransformation processes may result in the exposure of the liver (and other organs) to hepatotoxins, potentially interacting with cellular constituents and causing toxicity and various lesions. Hepatotoxicity can be investigated on a tissue, cellular and molecular level by employing various in vivo and in vitro techniques, including novel three-dimensional (3 D) cell culturing methods. This paper reflects on the liver and its myriad of functions and the influence of drug biotransformation on liver dysfunction. Current in vivo and in vitro models used to study liver function and dysfunction is outlined, emphasizing their advantages and disadvantages. The advantages of novel in vitro 3 D cell culture models are discussed and the possibility of novel models to bridge the gap between in vitro and in vivo models is explained. Progression made in the field of cell culturing methods such as 3 D cell culturing techniques over the last decade promises to reduce the use of in vivo animal models in biotransformation and toxicological studies of the liver.

Recent developments in our understanding of the implications of traditional African medicine on drug metabolism.

INTRODUCTION: The use of traditional herbal medicines has become increasingly popular globally, but in some countries, it is the main or sometimes even the only healthcare service available in the most rural areas. This is especially true for Africa where herbal medicines form a key component of traditional medicinal practices and there is access to a diversity of medicinal plants. Although many benefits have been derived from the use of traditional herbal medicines, many concerns are associated with their use of which herb-drug interactions have been identified to have a rising impact on patient treatment outcome. One type of pharmacokinetic interaction involves the modulation of drug metabolizing enzymes, which may result in enhanced or reduced bioavailability of co-administered drugs. Areas covered: This review highlights the current information available on drug metabolism-associated information with regards to traditional African medicines related to some of the most prevalent diseases burdening the African continent. Expert opinion: It is clear from previous studies that enzyme modulation by traditional African medicines plays a significant role in the pharmacokinetics of some co-administered drugs, but more research is needed to provide detailed information on these interactions, specifically for treatment of prevalent diseases such as tuberculosis and hypertension.

Cell-free DNA in a three-dimensional spheroid cell culture model: A preliminary study.

BACKGROUND: Investigating the biological functions of cell-free DNA (cfDNA) is limited by the interference of vast numbers of putative sources and causes of DNA release into circulation. Utilization of three-dimensional (3D) spheroid cell cultures, models with characteristics closer to the in vivo state, may be of significant benefit for cfDNA research. METHODS: CfDNA was isolated from the growth medium of C3A spheroid cultures in rotating bioreactors during both normal growth and treatment with acetaminophen. Spheroid growth was monitored via planimetry, lactate dehydrogenase activity and glucose consumption and was related to isolated cfDNA characteristics. RESULTS: Changes in spheroid growth and stability were effectively mirrored by cfDNA characteristics. CfDNA characteristics correlated with that of previous two-dimensional (2D) cell culture and human plasma research. CONCLUSIONS: 3D spheroid cultures can serve as effective, simplified in vivo-simulating "closed-circuit" models since putative sources of cfDNA are limited to only the targeted cells. In addition, cfDNA can also serve as an alternative or auxiliary marker for tracking spheroid growth, development and culture stability. BIOLOGICAL SIGNIFICANCE: 3D cell cultures can be used to translate "closed-circuit" in vitro model research into data that is relevant for in vivo studies and clinical applications. In turn, the utilization of cfDNA during 3D culture research can optimize sample collection without affecting the stability of the growth environment. Combining 3D culture and cfDNA research could, therefore, optimize both research fields.