The effect of brassinolide, a plant steroid hormone, on drug resistant small-cell lung carcinoma cells

Molecular Interactions of the Plant Steroid Hormone Epibrassinolide on Human Drug-Sensitive and Drug-Resistant Small-Cell Lung Carcinoma Cells

Background: Small-cell lung cancer (SCLC) has a poor prognosis because it is often diagnosed after it has spread and develops multi-drug resistance. Epibrassinolide (EB) is a plant steroid hormone with widespread distribution and physiological effects. In plants, EB-activated gene expression occurs via a GSK-mediated signaling pathway, similar to Wnt-β-catenin signaling in animal cells that is elevated in cancer cells. Methods: This mechanistic parallel prompted investigations of the molecular interactions of EB on drug-sensitive (H69) and multi-drug-resistant (VPA) SCLC cells. Cellular and molecular investigations were performed. Results: Pharmacologic interactions between EB and the Wnt signaling inhibitors IGC-011 and PRI-724 were determined by the combination index method and showed antagonism, indicating that EB acts on the same pathway as these inhibitors. Following incubation of drug-sensitive and drug-resistant SCLC cells with EB, there was a reduction in β-catenin (e.g., 3.8 to 0.7 pg/µg protein), accompanied by a reduction in β-catenin promoter activity, measured by firefly luciferase-coupled promoter element transfection. Cellular β-catenin concentration is regulated by the active form of GSK3β. In Wnt signaling, active GSK3β is converted to inactive pGSK3β, thereby increasing the concentration of β-catenin. After incubation of SCLC cells with EB, there was a reduction in the inactive form (pGSK3β) and a relative increase in the active form (GSK3β). In vitro enzyme assays showed that EB did not inhibit purified GSK3β, but there was non-competitive inhibition when SCLC cell extracts were used as the source of enzyme. This indirect inhibition by EB indicates that it may act on the Wnt pathway by blocking the phosphorylation of GSK3β. The protein levels of three SCLC tumor markers, namely, NSE, CAV1, and MYCL1, were elevated in drug-resistant SCLC cells. EB incubation led to a significant reduction in the levels of the three markers. Two major effects of EB on SCLC cells are the promotion of apoptosis and the reversal of drug resistance. Transcriptional analyses showed that after exposure of SCLC cells to EB, there were increases in the expression of genes encoding apoptotic inducers (e.g., BAX and FAS) and effectors (e.g., CASP3) and reductions in the expression of genes encoding apoptosis inhibitors (e.g., survivin). PGP1 and MRP1, two membrane efflux pumps expressed in SCLC cells, were elevated in drug-resistant cells, but EB incubation did not affect these protein levels. Cellular assays of drug efflux by PGP1 showed an increase in drug-resistant cells, but EB did not alter efflux activity. Following exposure to human liver microsomes, EB was metabolized by NADPH-dependent oxidation and UDPG-dependent glucuronidation, as evidenced by the elimination of EB cytotoxicity against SCLC cells. Conclusions: Taken together, these data indicate that EB, a steroid hormone in plants consumed in the human diet, is pharmacologically active in drug-sensitive and drug-resistant SCLC cells in the Wnt signaling pathway, alters apoptotic gene expression, and is a substrate for microsomal modifications.

Screening and verification of antiviral compounds against HSV-1 using a method based on a plaque inhibition assay

BACKGROUND

Herpes simplex virus type 1 (HSV-1) infection is a common viral disease that mainly causes oral lesions, but can also cause genital lesions in some instances. Current treatments with nucleoside analogs are limited by the emergence of drug resistance. Therefore, novel anti-HSV-1 drugs are urgently needed.

METHODS

In this study, we screened a library of 2080 compounds for anti-HSV-1 activity using a plaque formation assay. We selected 11 potential inhibitors of HSV-1 and further evaluated their antiviral effects by plaque reduction assay and real-time polymerase chain reaction (qPCR).

RESULTS

Five compounds, namely ginsenoside Rd, brassinolide, rosamultin, 3'-hydroxy puerarin, and clinafloxacin HCl, showed potent anti-HSV-1 activity and completely suppressed plaque formation at a concentration of 10 µM. Among them, clinafloxacin HCl, a fluoroquinolone antibiotic, exhibited a high selectivity index for HSV-1.

CONCLUSIONS

Our findings suggest that these five compounds have potential antiviral properties against HSV-1 and may have different mechanisms of action. Further studies are warranted to elucidate the antiviral mechanisms of these compounds and to explore their therapeutic potential for HSV-1 infection.

Natural compounds: Wnt pathway inhibitors with therapeutic potential in lung cancer

The Wnt/β-catenin pathway is abnormally activated in most lung cancer tissues and considered to be an accelerator of carcinogenesis and lung cancer progression, which is closely related to increased morbidity rates, malignant progression, and treatment resistance. Although targeting the canonical Wnt/β-catenin pathway shows significant potential for lung cancer therapy, it still faces challenges owing to its complexity, tumor heterogeneity and wide physiological activity. Therefore, it is necessary to elucidate the role of the abnormal activation of the Wnt/β-catenin pathway in lung cancer progression. Moreover, Wnt inhibitors used in lung cancer clinical trials are expected to break existing therapeutic patterns, although their adverse effects limit the treatment window. This is the first study to summarize the research progress on various compounds, including natural products and derivatives, that target the canonical Wnt pathway in lung cancer to develop safer and more targeted drugs or alternatives. Various natural products have been found to inhibit Wnt/β-catenin in various ways, such as through upstream and downstream intervention pathways, and have shown encouraging preclinical anti-tumor efficacy. Their diversity and low toxicity make them a popular research topic, laying the foundation for further combination therapies and drug development.

Cancer and brassinosteroids: Mechanisms of action, SAR and future perspectives

Brassinosteroids are plant hormones whose main function is to stimulate plant growth. However, they have been studied for their biological applications in humans. Brassinosteroid compounds have displayed an important role in the study of cancer pathology and show potential for developing novel anticancer drugs. In this review we describe the relationship of brassinosteroids with cancer with focus on the last decade, the mechanisms of cytotoxic activity described to date, and a structure-activity relationship based on the available information.

Small-Molecule Inhibitors of Tankyrases as Prospective Therapeutics for Cancer

Tankyrases are multifunctional poly(adenosine diphosphate-ribose) polymerases that regulate diverse biological processes including telomere maintenance and cellular signaling. These processes are often implicated in a number of human diseases, with cancer being the most prevalent example. Accordingly, tankyrase inhibitors have gained increasing attention as potential therapeutics. Since the discovery of XAV939 and IWR-1 as the first tankyrase inhibitors over two decades ago, tankyrase-targeted drug discovery has made significant progress. This review starts with an introduction of tankyrases, with emphasis placed on their cancer-related functions. Small-molecule inhibitors of tankyrases are subsequently delineated based on their distinct modes of binding to the enzymes. In addition to inhibitors that compete with oxidized nicotinamide adenine dinucleotide (NAD⁺) for binding to the catalytic domain of tankyrases, non-NAD⁺-competitive inhibitors are detailed. This is followed by a description of three clinically trialled tankyrase inhibitors. To conclude, some of challenges and prospects in developing tankyrase-targeted cancer therapies are discussed.

Bee Collected Pollen and Bee Bread: Bioactive Constituents and Health Benefits

Bee products were historically used as a therapheutic approach and in food consumption, while more recent data include important details that could validate them as food supplements due to their bioproperties, which support their future use as medicines. In this review data, data collected from bee pollen (BP) and bee bread (BB) essays will be discussed and detailed for their nutritional and health protective properties as functional foods. Dietary antioxidants intake derived from BP and BB have been associated with the prevention and clinical treatment of multiple diseases. The beneficial effects of BP and BB on health result from the presence of multiple polyphenols which possess anti-inflammatory properties, phytosterols and fatty acids, which play anticancerogenic roles, as well as polysaccharides, which stimulate immunological activity. From the main bioactivity studies with BP and BB, in vitro studies and animal experiments, the stimulation of apoptosis and the inhibition of cell proliferation in multiple cell lines could be one of the major therapeutic adjuvant effects to be explored in reducing tumor growth. Tables summarizing the main data available in this field and information about other bio-effects of BP and BB, which support the conclusions, are provided. Additionally, a discussion about the research gaps will be presented to help further experiments that complete the tree main World Health Organization (WHO) Directives of Efficiency, Safety and Quality Control for these products.

Evaluation of biophysical as well as biochemical potential of curcumin and resveratrol during prostate cancer

Purpose: The present study evaluated biochemical as well as biophysical mechanisms behind the synergistic effects of curcumin and resveratrol during prostate carcinogenesis.Methods: The rats were segregated into five groups that included normal control, 3,2'-dimethyl-4-aminobiphenyl (DMAB)treated, DMAB + curcumin treated, DMAB + resveratrol-treated and DMAB + curcumin + resveratrol-treated.Results: The DMAB treatment resulted in a significant increase in the levels of lipid peroxidation (LPO) in DMAB treated rats. Also, significant changes were recorded in the enzyme activities of both drug metabolising enzyme and antioxidant enzymes after DMAB treatment. Further, radiorespirometric studies showed a significant increase in the ¹⁴C-glucose turnover as well as ¹⁴C-glucose uptake in the prostate slices of DMAB treated rats. Moreover, a significant rise in cell proliferation was confirmed indirectly by enhanced uptake of ³H-thymidine in the prostate slices of DMAB treated rats. Interestingly, combined treatment of curcumin and resveratrol to DMAB treated animals resulted in a significant decrease in lipid peroxidation, ¹⁴C glucose uptakes/turnover and ³H-thymidine uptake in the DMAB treated rats. Besides this, curcumin and resveratrol in combination significantly modulated biochemical indices including drug-metabolising enzymes; antioxidant enzymes in DMBA treated rats.Conclusion: The study, therefore, concludes that the combination of curcumin and resveratrol holds strong modulatory potential against prostate carcinogenesis.

Negative regulators of Wnt signaling in non-small cell lung cancer: Theoretical basis and therapeutic potency

Significant advances in the treatment of non-small cell lung cancer (NSCLC) have been made over the past decade, and they predominantly involve molecular targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. However, despite the initial good response, drug resistance eventually develops. The Wnt signaling pathway has recently been considered important in embryonic development and tumorigenesis in many cancers, particularly NSCLC. Moreover, the aberrant Wnt pathway plays a significant role in NSCLC and is associated with cancer cell proliferation, metastasis, invasion and drug resistance, and the suppression of canonical or noncanonical Wnt signaling through various biological or pharmacological negative regulators has been proven to produce specific anticancer effects. Thus, blocking the Wnt pathway via its negative regulators may overcome the resistance of current treatment methods and lead to new treatment strategies for NSCLC. Therefore, in this review, we summarize recent studies on the role of negative regulators in Wnt signaling in NSCLC and the therapeutic potency of these molecules as agents and targets for NSCLC treatments.

Phytoestrogens, phytosteroids and saponins in vegetables: Biosynthesis, functions, health effects and practical applications

Phytoestrogens are non-steroidal secondary metabolites with similarities in structure and biological activities with human estrogens divided into various classes of compounds, including lignans, isoflavones, ellagitannins, coumestans and stilbenes. Similarly, phytosteroids are steroidal compounds of plant origin which have estrogenic effects and can act as agonists, antagonists, or have a mixed agonistic/antagonistic activity to animal steroid receptors. On the other hand, saponins are widely distributed plant glucosides divided into triterpenoid and steroidal saponins that contribute to plant defense mechanism against herbivores. They present a great variation from a structural point of view, including compounds from different classes. In this chapter, the main vegetable sources of these compounds will be presented, while details regarding their biosynthesis and plant functions will be also discussed. Moreover, considering the significant bioactive properties that these compounds exhibit, special focus will be given on their health effects, either beneficial or adverse. The practical applications of these compounds in agriculture and phytomedicine will be also demonstrated, as well as the future prospects for related research.

Polyphosphazene-based nanocarriers for the release of agrochemicals and potential anticancer drugs

The synthesised polyphosphazene-based nanocarriers allowed sustained diosgenin and brassinosteroid release over 4 days, with strong to moderate MCF-7 cytotoxicity and good agrochemical activity at medium and low concentrations.

Potential of curcumin and resveratrol as biochemical and biophysical modulators during lung cancer in rats

The present study explored chemopreventive aspects of curcumin and resveratrol in the experimental model of lung carcinogenesis in rats. The main aim was to establish efficacy of combined phytochemicals treatment over individual treatments in rat cancer model. The study was performed in terms of both biophysical and biochemical parameters. The rats were segregated into five groups, which included normal control, benzo[a]pyrene (BP) treated, BP + curcumin treated, BP + resveratrol treated, and BP + curcumin + resveratrol treated groups. The results confirmed significant changes in the biochemical indices of the BP treated rats. Further, radiorespirometric studies showed significant rise in the ¹⁴C-glucose turnover and uptakes in BP treated rats. Also, a significant increase in the cell proliferation was noticed indirectly by recording uptakes of ³H-thymidine in the lung slices of BP treated rats. On the other hand, supplementation with curcumin and resveratrol in combination to BP treated rats significantly modulated both biophysical and biochemical indices. The histopathological studies also supported the efficacy of combined treatment of phytochemicals during lung carcinogenesis. The present study concluded that the combination of curcumin and resveratrol efficiently modulated lung carcinogenesis in rats.