Cytostatic and Cytotoxic Natural Products against Cancer Cell Models

Plants with Anti-Ulcer Activity and Mechanism: A Review of Preclinical and Clinical Studies

Ulcer disorders including the oral mucosa, large intestine, and stomach mucosa, cause significant global health burdens. Conventional treatments such as non-steroid anti-inflammatory drugs (NSAIDs), proton pump inhibitors (PPIs), histamine H2 receptor antagonists (H2RAs), and cytoprotective agents have drawbacks like mucosal injury, diminish gastric acid secretion, and interact with concurrent medications. Therefore, alternative therapeutic approaches are needed to tackle this health concern. Plants are rich in active metabolites in the bark, roots, leaves, fruits, and seeds, and have been utilized for medicinal purposes since ancient times. The use of herbal therapy is crucial, and regulations are necessary to ensure the quality of products, particularly in randomized studies, to assess their efficacy and safety in treating ulcer disorders. This study aims to explore the anti-ulcer activity of medicinal plants in treating peptic ulcer disease, ulcerative colitis, and aphthous ulcers. Articles were searched in Scopus and PubMed, and filtered for publication from 2013 to 2023, resulting in a total of 460 from Scopus and 239 from PubMed. The articles were further screened by title and abstract and resulted in 55 articles. Natural products, rich in active metabolites, were described to manage ulcer disease by protecting the mucosa, reducing ulcer effects, inhibiting pro-inflammatory factors, and reducing bacterial load, thus improving patients' quality of life. Natural extracts have proven effective in managing other health problems, including ulcers by reducing pain and decreasing lesions. This review provides an overview of preclinical and clinical studies on medicinal plants, focusing on their effectiveness in treating conditions like peptic ulcers, ulcerative colitis, and aphthous ulcers.

Evaluation of Biological Activity of Natural Compounds: Current Trends and Methods

Natural compounds have diverse structures and are present in different forms of life. Metabolites such as tannins, anthocyanins, and alkaloids, among others, serve as a defense mechanism in live organisms and are undoubtedly compounds of interest for the food, cosmetic, and pharmaceutical industries. Plants, bacteria, and insects represent sources of biomolecules with diverse activities, which are in many cases poorly studied. To use these molecules for different applications, it is essential to know their structure, concentrations, and biological activity potential. In vitro techniques that evaluate the biological activity of the molecules of interest have been developed since the 1950s. Currently, different methodologies have emerged to overcome some of the limitations of these traditional techniques, mainly via reductions in time and costs. These emerging technologies continue to appear due to the urgent need to expand the analysis capacity of a growing number of reported biomolecules. This review presents an updated summary of the conventional and relevant methods to evaluate the natural compounds’ biological activity in vitro.

Design and Development of a New Type of Hybrid PLGA/Lipid Nanoparticle as an Ursolic Acid Delivery System against Pancreatic Ductal Adenocarcinoma Cells

Despite many attempts, trials, and treatment procedures, pancreatic ductal adenocarcinoma (PDAC) still ranks among the most deadly and treatment-resistant types of cancer. Hence, there is still an urgent need to develop new molecules, drugs, and therapeutic methods against PDAC. Naturally derived compounds, such as pentacyclic terpenoids, have gained attention because of their high cytotoxic activity toward pancreatic cancer cells. Ursolic acid (UA), as an example, possesses a wide anticancer activity spectrum and can potentially be a good candidate for anti-PDAC therapy. However, due to its minimal water solubility, it is necessary to prepare an optimal nano-sized vehicle to overcome the low bioavailability issue. Poly(lactic-co-glycolic acid) (PLGA) polymeric nanocarriers seem to be an essential tool for ursolic acid delivery and can overcome the lack of biological activity observed after being incorporated within liposomes. PLGA modification, with the addition of PEGylated phospholipids forming the lipid shell around the polymeric core, can provide additional beneficial properties to the designed nanocarrier. We prepared UA-loaded hybrid PLGA/lipid nanoparticles using a nanoprecipitation method and subsequently performed an MTT cytotoxicity assay for AsPC-1 and BxPC-3 cells and determined the hemolytic effect on human erythrocytes with transmission electron microscopic (TEM) visualization of the nanoparticles and their cellular uptake. Hybrid UA-loaded lipid nanoparticles were also examined in terms of their stability, coating dynamics, and ursolic acid loading. We established innovative and repeatable preparation procedures for novel hybrid nanoparticles and obtained biologically active nanocarriers for ursolic acid with an IC50 below 20 µM, with an appropriate size for intravenous dosage (around 150 nm), high homogeneity of the sample (below 0.2), satisfactory encapsulation efficiency (up to 70%) and excellent stability. The new type of hybrid UA-PLGA nanoparticles represents a further step in the development of potentially effective PDAC therapies based on novel, biologically active, and promising triterpenoids.

Cytotoxicity of Peruvian propolis and Psidium guajava on human gingival fibroblasts, PBMCs and HeLa cells

It is indisputable that every day it is demonstrated that natural products present diverse therapeutic benefits, which has boosted their incorporation within various products for clinical use. However, this must be accompanied by knowledge of their effect on cell lines to ensure their use is safe. The objective of this study was to evaluate the cytotoxic effect of two ethanolic extracts based on Peruvian natural products, on three human cell lines. Cervical cancer cell lines (HeLa), human gingival fibroblasts (HGF-1 - ATCC CRL-2014) (HGF-1) and peripheral blood mononuclear cells (PBMCs) were cultured and subsequently treated with preparations of ethanolic extracts of propolis (EEP) and Psidium guajava (EEG) from a concentration of 50 mg/mL to 0.024 mg/mL, by the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazole bromide reduction assay. At a concentration of 0.24 mg/mL EEG, viability of 99.7±1.24%, 99.8±2.2% and 99.7±2.7% was observed in HeLa, HGF-1 and PBMCs, respectively; >90% cell viability values were observed with EPP at 0.024 mg/mL, with HGF-1 showing the highest viability (96.9±1.15%). A dose-dependent effect was observed for both extracts with a decrease in cell viability as concentrations increased (up to 50 mg/mL). EEP and EEG extracts at low concentrations do not show cytotoxicity in human cell lines, these findings are an advance in the preclinical evaluation on their safety and open a continuity to further studies for their potential applications in dentistry and medicine.

Cytotoxicity of Peruvian propolis and Psidium guajava on human gingival fibroblasts, PBMCs and HeLa cells

It is indisputable that every day it is demonstrated that natural products present diverse therapeutic benefits, which has boosted their incorporation within various products for clinical use. However, this must be accompanied by knowledge of their effect on cell lines to ensure their use is safe. The objective of this study was to evaluate the cytotoxic effect of two ethanolic extracts based on Peruvian natural products, on three human cell lines. Cervical cancer cell lines (HeLa), human gingival fibroblasts (HGF-1 - ATCC CRL-2014) (HGF-1) and peripheral blood mononuclear cells (PBMCs) were cultured and subsequently treated with preparations of ethanolic extracts of propolis (EEP) and Psidium guajava (EEG) from a concentration of 50 mg/mL to 0.024 mg/mL, by the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazole bromide reduction assay. At a concentration of 0.24 mg/mL EEG, viability of 99.7±1.24%, 99.8±2.2% and 99.7±2.7% was observed in HeLa, HGF-1 and PBMCs, respectively; >90% cell viability values were observed with EPP at 0.024 mg/mL, with HGF-1 showing the highest viability (96.9±1.15%). A dose-dependent effect was observed for both extracts with a decrease in cell viability as concentrations increased (up to 50 mg/mL). EEP and EEG extracts at low concentrations do not show cytotoxicity in human cell lines, these findings are an advance in the preclinical evaluation on their safety and open a continuity to further studies for their potential applications in dentistry and medicine.

Cephalotaxine-type alkaloids from the seeds of Cephalotaxus fortunei and their cytotoxic activities

Six new Cephalotaxus alkaloids, including five cephalotaxine-type alkaloids, and one homoerythrina-type alkaloid, along with six known analogues, were isolated from the seeds of Cephalotaxus fortunei. Their structures were elucidated by combination of spectroscopic data analyses, time-dependent density functional theory (TDDFT) ECD calculation, and single-crystal X-ray diffraction. Cephalofortine B represents the first example of C-5 epi-cephalotaxine-type alkaloid. All isolated compounds were tested for cytotoxicities against HCT-116, A375, and SK-Mel-28 cell lines. Cephalofortine E showed moderate activity against HCT-116 cell line, with an IC₅₀ value of 7.46 ± 0.77 μM.

CBP/p300 Bromodomain Inhibitor-I-CBP112 Declines Transcription of the Key ABC Transporters and Sensitizes Cancer Cells to Chemotherapy Drugs

Simple Summary

Despite tremendous advances in cancer treatment, chemotherapy remains the first-line choice in many tumor types. The action of numerous chemotherapy drugs is limited by the occurrence of ABC proteins in cancer cell membranes, which remove medicines from cell compartments. In this paper, we show that one of bromodomain inhibitors, namely I-CBP112, was capable of repressing genes that are responsible for multidrug resistance in all three studied cancer cell lines. CBP/p300 bromodomain inhibitor allows for the higher drug accumulation inside cells and considerably potentiated drug effects. At the molecular level, I-CBP112 caused rearrangement of chromatin at the ABC gene promoters by inducing recruitment of LSD1, which removes transcription-promoting histone marks. I-CBP112 emerges as a promising compound to overcome ABC-dependent cancer drug resistance.

Abstract

The high expression of some ATP-binding cassette (ABC) transporters is linked to multidrug resistance in cancer cells. We aimed to determine if I-CBP112, which is a CBP/p300 bromodomain inhibitor, altered the vulnerability of the MDA-MB-231 cell line to chemotherapy drugs, which are used in neoadjuvant therapy in patients with triple negative breast cancer (TNBC). MDA-MB-231 cells represent TNBC, which is negative for the expression of estrogen and progesterone receptors and HER2 protein. An I-CBP112-induced decrease in the expression of all the studied ABCs in the breast, but also in the lung (A549), and hepatic (HepG2) cancer cell lines was associated with increased accumulation of doxorubicin, daunorubicin, and methotrexate inside the cells as well as with considerable cell sensitization to a wide range of chemotherapeutics. Gene promoters repressed by I-CBP112 in MDA-MB-231 cells, such as ABCC1 and ABCC10, were characterized by enhanced nucleosome acetylation and, simultaneously, by considerably lower trimethylation in the transcription-promoting form of H3K4me3. The CBP/p300 bromodomain inhibitor induced the recruitment of LSD1 to the gene promoters. The inhibition of this demethylase in the presence of I-CBP112 prevented the repression of ABCC1 and ABCC10 and, to a considerable extent, cancer cells’ sensitization to drugs. In conclusion, the CBP/p300 bromodomain inhibitor I-CBP112 can be considered as a potent anti-multidrug-resistance agent, capable of repressing key ABC transporters responsible for drug efflux in various cancer types.

Evaluation of the In Vitro Cytotoxic Activity of Ursolic Acid PLGA Nanoparticles against Pancreatic Ductal Adenocarcinoma Cell Lines

Among all the types of cancer, Pancreatic Ductal Adenocarcinoma remains one of the deadliest and hardest to fight and there is a critical unmet need for new drugs and therapies for its treatment. Naturally derived compounds, such as pentacyclic triterpenoids, have gathered attention because of their high cytotoxic potential towards pancreatic cancer cells, with a wide biological activity spectrum, with ursolic acid (UA) being one of the most interesting. However, due to its minimal water solubility, it is necessary to prepare a nanocarrier vehicle to aid in the delivery of this compound. Poly(lactic-co-glycolic acid) or PLGA polymeric nanocarriers are an essential tool for ursolic acid delivery and can overcome the lack in its biological activity observed after incorporating within liposomes. We prepared UA-PLGA nanoparticles with a PEG modification, to achieve a long circulation time, by using a nanoprecipitation method and subsequently performed an MTT cytotoxicity assay towards AsPC-1 and BxPC-3 cells, with TEM visualization of the nanoparticles and their cellular uptake. We established repeatable preparation procedures of the nanoparticles and achieved biologically active nanocarriers with an IC50 below 30 µM, with an appropriate size for intravenous dosage (around 140 nm), high sample homogeneity (below 0.2) and reasonable encapsulation efficiency (up to 50%). These results represent the first steps in the development of potentially effective PDAC therapies based on novel biologically active and promising triterpenoids.

In Vitro Anticancer Drug Sensitivity Sensing through Single-Cell Raman Spectroscopy

Traditional in vitro anticancer drug sensitivity testing at the population level suffers from lengthy procedures and high false positive rates. To overcome these defects, we built a confocal Raman microscopy sensing system and proposed a single-cell approach via Raman-deuterium isotope probing (Raman-DIP) as a rapid and reliable in vitro drug efficacy evaluation method. Raman-DIP detected the incorporation of deuterium into the cell, which correlated with the metabolic activity of the cell. The human non-small cell lung cancer cell line HCC827 and human breast cancer cell line MCF-7 were tested against eight different anticancer drugs. The metabolic activity of cancer cells could be detected as early as 12 h, independent of cell growth. Incubation of cells in 30% heavy water (D₂O) did not show any negative effect on cell viability. Compared with traditional methods, Raman-DIP could accurately determine the drug effect, meanwhile, it could reduce the testing period from 72–144 h to 48 h. Moreover, the heterogeneity of cells responding to anticancer drugs was observed at the single-cell level. This proof-of-concept study demonstrated the potential of Raman-DIP to be a reliable tool for cancer drug discovery and drug susceptibility testing.

Proapoptotic and proautophagic activity of 20-hydroxyecdysone in breast cancer cells in vitro

The present study was designed to identify the biological activity of three ecdysones, i.e., 20-hydroxyecdysone (20-HE), ajugasterone C, and polypodine B isolated from Serratula coronata. The main objective was to investigate the molecular mechanism of the biological activity of those compounds and to assess their impact on breast cancer cell survival and cell cycle. Cell lines were selected according to their hormone receptor status since this factor is perceived as a crucial one in the cancer prognosis as well as cancer cell response to therapy. Consequently, MCF7 (ER/PR+, HER2-), T-47D (ER/PR+, HER2-/+), and MDA-MB-231 (ER/PR-, HER2-) were enrolled in the study. Additionally, a non-tumorigenic, MCF10A cells were selected to verify any potential specificity to cancer cells. Interestingly, none of the studied compounds affected the viability of MCF10A cells while cancer cells were altered, albeit in different ways. Polypodine B did not affect the viability or cell cycle distribution of studied breast cancer cells. By contrast, 20-HE and ajugasterone C significantly inhibited the viability of triple-negative cell line, MDA-MB-231. Interestingly, 20-HE revealed proapoptotic activity in MDA-MB-231 and T-47D cells that was manifested by alterations in PARP, Bax, and Bcl-2 levels as well as caspase-3 activation. Moreover, 20-HE induced autophagy that was mediated by modification of autophagy-associated proteins, i.e., LC3, p62, and mTOR, but only in MDA-MB-231 cells. This study is the first to report diverse biological activity of phytoecdysones in different breast cancer cells, that suggests association with molecular characteristics including receptor status but also other biological properties and genetic markers.

Fortuneicyclidins A and B, Pyrrolizidine Alkaloids with a 7-Azatetracyclo[5.4.3.0.02,8]tridecane Core, from Cephalotaxus fortunei

Fortuneicyclidins A (1) and B (2), a pair of epimeric pyrrolizidine alkaloids containing an unprecedented 7-azatetracyclo[5.4.3.0.0^2,8]tridecane core, were isolated from the seeds of Cephalotaxus fortunei, along with two biogenetically relative known analogues, 3 and 4. The structures were determined by multiple spectral techniques and chemical derivatization methods. Compound 1 showed inhibitory activity against α-glucosidase.

Cell-based multi-target QSAR model for design of virtual versatile inhibitors of liver cancer cell lines

Liver cancers are one of the leading fatal diseases among malignant neoplasms. Current chemotherapeutic treatments used to fight these illnesses have become less efficient in terms of both efficacy and safety. Therefore, there is a great need of search for new anti-liver cancer agents and this can be accelerated by using computer-aided drug discovery approaches. In this work, we report the development of the first cell-based multi-target model based on quantitative structure-activity relationships (CBMT-QSAR) for the design and prediction of chemicals as anticancer agents against 17 liver cancer cell lines. While having a good quality and predictive power (accuracy higher than 80%) in the training and test sets, respectively, the CBMT-QSAR model was employed as a tool to directly extract suitable fragments from the physicochemical and structural interpretations of the molecular descriptors. Some of these desirable fragments were assembled, leading to the virtual design of eight molecules with drug-like properties, with six of them being predicted as versatile anticancer agents against the 17 liver cancer cell lines reported here.

Crocin treatment promotes the oxidative stress and apoptosis in human thyroid cancer cells FTC-133 through the inhibition of STAT/JAK signaling pathway

Thyroid cancer is the most frequent endocrine malignancy, which accounts for nearly 1% of all the cancer worldwide. Crocin has a diverse biological function, such as anti-cancer, anti-inflammatory and antioxidant functions, specifically in the respiratory related diseases. Using in vitro techniques, this work was intended to illuminate the anti-cancer effect of crocin in follicular thyroid carcinoma (FTC) (FT 133 cells), and the potential molecular mechanism convoluted. The outcome of the present work showed that crocin was able to prevent the proliferation and triggering the apoptosis in a dose-dependent mode, of FTC-133 cells by methyl thiazolyldiphenyl-tetrazolium bromide and staining assay (acridine orange/propiduim iodide [PI], 4',6-diamidino-2-phenylindole, and PI dye). Crocin did not show toxicity to the normal thyroid (PCCL3) cells. Crocin-induced reactive oxygen species, mitochondrial membrane potential activity, caspase-8 and -9, lipid peroxidation (thiobarbituric acid reactive substances) activity while suppressing antioxidant activity (superoxide dismutase, catalase, and glutathione) in FTC-133 cells. In addition, crocin was also participated in a halting of the proteins related to cell cycle, cyclin D1, and pro-apoptotic proteins; Bax and caspase-3 expression, together with the elevation of anti-apoptotic factor Bcl-2. Further, crocin have a dual inhibition of two major pathways, nuclear factor-κB, extracellular signal-regulated kinase, and janus kinase-signal transducer and activator of transcription signaling pathways. In conclusion, crocin can inhibit follicular thyroid carcinoma proliferation and promote cell apoptosis.

New Conjugates of Polyhydroxysteroids with Long-Chain Fatty Acids from the Deep-Water Far Eastern Starfish Ceramaster patagonicus and Their Anticancer Activity

Four new conjugates, esters of polyhydroxysteroids with long-chain fatty acids (1–4), were isolated from the deep-water Far Eastern starfish Ceramaster patagonicus. The structures of 1–4 were established by NMR and ESIMS techniques as well as chemical transformations. Unusual compounds 1–4 contain the same 5α-cholestane-3β,6β,15α,16β,26-pentahydroxysteroidal moiety and differ from each other in the fatty acid units: 5′Z,11′Z-octadecadienoic (1), 11′Z-octadecenoic (2), 5′Z,11′Z-eicosadienoic (3), and 7′Z-eicosenoic (4) acids. Previously, only one such steroid conjugate with a fatty acid was known from starfish. After 72 h of cell incubation, using MTS assay it was found that the concentrations of compounds 1, 2, and 3 that caused 50% inhibition of growth (IC₅₀) of JB6 Cl41 cells were 81, 40, and 79 µM, respectively; for MDA-MB-231 cells, IC₅₀ of compounds 1, 2, and 3 were 74, 33, and 73 µM, respectively; for HCT 116 cells, IC₅₀ of compounds 1, 2, and 3 were 73, 31, and 71 µM, respectively. Compound 4 was non-toxic against tested cell lines even in three days of treatment. Compound 2 (20 µM) suppressed colony formation and migration of MDA-MB-231 and HCT 116 cells.

Identification of rapid access to polycyclic systems via a base-catalyzed cascade cyclization reaction and their biological evaluation

A base-mediated cascade reaction between malonate esters and acrolein was developed to access complex polycyclic systems. This novel tandem reaction enables the simultaneous generation of up to seven new bonds and at least three new stereogenic centers. Mechanistic studies indicate a series of nucleophilic 1,4 and 1,6 Michael addition reactions occur, followed by an aldol condensation reaction, culminating in the formation of three fused rings. The compounds were characterized by NMR studies and the stereochemistry was confirmed by X-ray analysis. The ability to generate multigram quantities of such complex molecular scaffolds renders the method promising for medicinal chemistry campaigns. Herein, we also demonstrate that the lead compounds display promising anti-proliferative activities against human cancer cell models.