Characteristic features of cytotoxic activity of flavonoids on human cervical cancer cells

HPLC-ESI/MS-MS metabolic profiling of white pitaya fruit and cytotoxic potential against cervical cancer: Comparative studies, synergistic effects, and molecular mechanistic approaches

Natural approach became a high demand for the prevention and treatment of such diseases for their proven safety and efficacy. This study is aimed to perform comparative phytochemical analysis of white pitaya (Hylocereus undatus) peel, pulp and seed extracts via determination of total flavonoid content, phenolic content, and antioxidant capacity, coupled with HPLC-ESI/MS-MS analysis. Further, we evaluated the synergistic cytotoxic potential with Cisplatin against cervical cancer cells with investigation of underlying mechanism. The highest content of phenolics and antioxidants were found in both seed and peel extracts. The HPLC-ESI/MS-MS revealed identification of flavonoids, phenolic acids, anthocyanin glycosides, lignans, stilbenes, and coumarins. The cytotoxicity effects were evaluated by MTT assay against prostate, breast and cervical (HeLa) and Vero cell lines. The seed and peel extracts showed remarkable cytotoxic effect against all tested cell lines. Moreover, the selectivity index confirmed high selectivity of pitaya extracts to cancer cells and safety on normal cells. The combined therapy with Cisplatin effectively enhanced its efficacy and optimized the treatment outcomes, through the apoptotic ability of pitaya extracts in HeLa cells, as evaluated by flow cytometry. Besides, RT-PCR and western blotting analysis showed downregulation of Bcl-2 and overexpression of P53, BAX among HeLa cells treated with pitaya extracts, which eventually activated apoptosis process. Thus, pitaya extract could be used as adjuvant therapy with cisplatin for treatment of cervical cancer. Furthermore, in-vivo extensive studies on the seed and peel extracts, and their compounds are recommended to gain more clarification about the required dose, and side effects.

Molecules Inducing Dental Stem Cells Differentiation and Bone Regeneration: State of the Art

Teeth include mesenchymal stem cells (MSCs), which are multipotent cells that promote tooth growth and repair. Dental tissues, specifically the dental pulp and the dental bud, constitute a relevant source of multipotent stem cells, known as dental-derived stem cells (d-DSCs): dental pulp stem cells (DPSCs) and dental bud stem cells (DBSCs). Cell treatment with bone-associated factors and stimulation with small molecule compounds are, among the available methods, the ones who show excellent advantages promoting stem cell differentiation and osteogenesis. Recently, attention has been paid to studies on natural and non-natural compounds. Many fruits, vegetables, and some drugs contain molecules that can enhance MSC osteogenic differentiation and therefore bone formation. The purpose of this review is to examine research work over the past 10 years that has investigated two different types of MSCs from dental tissues that are attractive targets for bone tissue engineering: DPSCs and DBSCs. The reconstruction of bone defects, in fact, is still a challenge and therefore more research is needed; the articles reviewed are meant to identify compounds useful to stimulate d-DSC proliferation and osteogenic differentiation. We only consider the results of the research which is encouraging, assuming that the mentioned compounds are of some importance for bone regeneration.

Untold story of human cervical cancers: HPV-negative cervical cancer

Cervical cancer is the fourth most common malignancy in women worldwide. Although infection from human papillomavirus (HPV) has been the leading cause of cervical cancer, HPV-negative cervical cancer accounts for approximately 3-8% of all cases. Previous research studies on cervical cancer have focused on HPV-positive cervical cancer due to its prevalence, resulting in HPV-negative cervical cancer receiving considerably less attention. As a result, HPV-negative cervical cancer is poorly understood. Its etiology remains elusive mainly due to limitations in research methodology such as lack of defined markers and model systems. Moreover, false HPV negativity can arise from inaccurate diagnostic methods, which also hinders the progress of research on HPV-negative cervical cancer. Since HPV-negative cervical cancer is associated with worse clinical features, greater attention is required to understand HPV-negative carcinoma. In this review, we provide a summary of knowledge gaps and current limitations of HPV-negative cervical cancer research based on current clinical statistics. We also discuss future directions for understanding the pathogenesis of HPV-independent cervical cancer. [BMB Reports 2022; 55(9): 429-438].

Comprehensive characterization of tumor microenvironment and m6A RNA methylation regulators and its effects on PD-L1 and immune infiltrates in cervical cancer

Understanding the role of N6-adenosine methylation (m6A) in the tumor microenvironment (TME) is important since it can contribute to tumor development. However, the research investigating the association between m6A and TME and cervical cancer is still in its early stages. The aim of this study was to discover the possible relationship between m6A RNA methylation regulators, TME, PD-L1 expression levels, and immune infiltration in cervical cancer. We gathered RNA-seq transcriptome data and clinical information from cervical cancer patients using The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. To begin, researchers assessed the differences in m6A regulatory factor expression levels between cervical cancer and normal tissues. Clustering analysis was adapted to assess PD-L1 expression, immunological score, immune cell infiltration, TME, and probable pathways in cervical cancer samples. The majority of m6A regulators were found to be considerably overexpressed in cervical cancer tissues. Using consensus clustering of 21 m6A regulators, we identified two subtypes (clusters 1/2) of cervical cancer, and we found that WHO stage and grade were associated with the subtypes. PD-L1 expression increased dramatically in cervical cancer tissues and was significantly linked to ALKBH5, FTO, METTL3, RBM15B, YTHDF1, YTHDF3, and ZC3H13 expression levels. Plasma cells and regulatory T cells (Tregs) were considerably elevated in cluster 2. Cluster 1 is involved in numerous signature pathways, including basal transcription factors, cell cycle, RNA degradation, and the spliceosome. The prognostic signature-based riskscore (METTL16, YTHDF1, and ZC3H13) was found to be an independent prognostic indicator of cervical cancer. The tumor immune microenvironment (TIME) was linked to m6A methylation regulators, and changes in their copy number will affect the quantity of tumor-infiltrating immune cells dynamically. Overall, our research discovered a powerful predictive signature based on m6A RNA methylation regulators. This signature correctly predicted the prognosis of cervical cancer patients. The m6A methylation regulator could be a critical mediator of PD-L1 expression and immune cell infiltration, and it could have a significant impact on the TIME of cervical cancer.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

Phenethyl Isothiocyanate Induces Apoptosis Through ROS Generation and Caspase-3 Activation in Cervical Cancer Cells

The latest research shows that current chemotherapeutics are ineffective because of the development of resistance in cervical cancer cells, and hence, their scope of use is limited. The main concern of researchers at the moment is the discovery of safe and effective antiproliferative plant chemicals that can aid in the battle against cervical cancer. Previous studies have shown the possible anticancer potential of phenethyl isothiocyanate obtained from cruciferous plants for many cancers, which targets various signaling pathways to exercise chemopreventive and therapeutic effects. This provides the basis for studying phenethyl isothiocyanate's therapeutic potential against cervical cancer. In the present study, cervical cancer cells were treated with various doses of phenethyl isothiocyanate, alone and in combination with cisplatin. Phenethyl isothiocyanate alone was sufficient to cause nucleus condensation and fragmentation and induce apoptosis in cervical cancer cells, but evident synergistic effects were observed in combination with cisplatin. In addition, phenethyl isothiocyanate treatment increased the production of intracellular ROS in a dose-dependent manner in cervical cancer cells. Furthermore, investigation of phenethyl isothiocyanate induced mitochondrial reactive oxygen species production, and activation of caspases showed that phenethyl isothiocyanate significantly activated caspase-3.

PPI Modulators of E6 as Potential Targeted Therapeutics for Cervical Cancer: Progress and Challenges in Targeting E6

Advanced cervical cancer is primarily managed using cytotoxic therapies, despite evidence of limited efficacy and known toxicity. There is a current lack of alternative therapeutics to treat the disease more effectively. As such, there have been more research endeavors to develop targeted therapies directed at oncogenic host cellular targets over the past 4 decades, but thus far, only marginal gains in survival have been realized. The E6 oncoprotein, a protein of human papillomavirus origin that functionally inactivates various cellular antitumor proteins through protein–protein interactions (PPIs), represents an alternative target and intriguing opportunity to identify novel and potentially effective therapies to treat cervical cancer. Published research has reported a number of peptide and small-molecule modulators targeting the PPIs of E6 in various cell-based models. However, the reported compounds have rarely been well characterized in animal or human subjects. This indicates that while notable progress has been made in targeting E6, more extensive research is needed to accelerate the optimization of leads. In this review, we summarize the current knowledge and understanding of specific E6 PPI inhibition, the progress and challenges being faced, and potential approaches that can be utilized to identify novel and potent PPI inhibitors for cervical cancer treatment.

A high-content AlphaScreen™ identifies E6-specific small molecule inhibitors as potential therapeutics for HPV+ head and neck squamous cell carcinomas

The incidence of human papillomavirus-positive head and neck squamous cell carcinoma (HPV⁺-HNSCC) has increased dramatically over the past decades due to an increase in infection of the oral mucosa by HPV. The etiology of HPV⁺-HNSCC is linked to expression of the HPV oncoprotein, E6, which influences tumor formation, growth and survival. E6 effects this oncogenic phenotype in part through inhibitory protein-protein interactions (PPIs) and accelerated degradation of proteins with tumor suppressor properties, such as p53 and caspase 8. Interfering with the binding between E6 and its cellular partners may therefore represent a reasonable pharmacological intervention in HPV⁺ tumors. In this study, we probed a small-molecule library using AlphaScreen™ technology to discover novel E6 inhibitors. Following a cascade of screens we identified and prioritized one hit compound. Structure activity relationship (SAR) studies of this lead uncovered an analog, 30-hydroxygambogic acid (GA-OH), that displayed improved activity. Further testing of this analog in a panel of HPV⁺ and HPV^- cell lines showed good potency and a large window of selectivity as demonstrated by apoptosis induction and significant inhibition of cell growth, cell survival in HPV⁺ cells. In summary, GA-OH may serve as a starting point for the development of potent E6-specific inhibitors.

Wogonoside promotes apoptosis and ER stress in human gastric cancer cells by regulating the IRE1α pathway

Gastric cancer is a disease that occurs in the digestive system of humans and remains a problem in the medical field. Wogonoside, a natural flavonoid, has been reported to exert antitumor effects on various types of tumors. However, the effects of wogonoside on gastric cancer remain elusive. The aim of the present study was to detect whether wogonoside treatment could induce apoptosis and ER stress in gastric cancer cells. In the present study, CCK-8 assay was used to detect the cell viability, Annexin V/PI staining was used to detect the cells apoptosis, western blot analysis and real-time PCR analysis was used to detect the endoplasmic reticulum (ER) stress in the AGS and MKN-45 gastric cancer cell lines. Wogonoside treatment reduced the viability of AGS and MKN-45 cells and induced apoptosis. Furthermore, the expression level of caspase-3 and -9 significantly increased following wogonoside treatment compared with that in non-treated cells, and the protein expression levels of proapoptotic Bax and antiapoptotic Bcl-2 increased and decreased, respectively compared with that in the control group. In addition, the phosphorylated protein expression levels of mitogen-activated protein kinase kinase 5 (ASK1) and JNK increased following wogonoside treatment, and the protein expression levels of tumor necrosis factor receptor-associated factor 2 (TRAF2) and serine/threonine-protein kinase/endoribonuclease IRE1 (IRE1α) were also increased following treatment with 50 µM wogonoside for 48 h. Furthermore, the interactions between IRE1α, TRAF2 and ASK1 significantly increased following wogonoside treatment, suggesting that wogonoside induced endoplasmic reticulum (ER) stress in the AGS and MKN-45 cell lines. In addition, small interfering RNA-mediated silencing of IRE1α suppressed the activity of the IRE1α-TRAF2-ASK1 complex and prevented wogonoside-induced cell apoptosis. In conclusion, the results of the present study suggested that wogonoside exhibited antitumor activity by inducing ER stress-associated cell death through the IRE1α-TRAF2-ASK1 pathway.

Chrysin induces osteogenic differentiation of human dental pulp stem cells

OBJECTIVES

As an ideal cell source for tissue engineering and bone defect repair, dental pulp stem cells (DPSCs) have good osteogenic differentiation potential. Chrysin, a flavonoid extracted from oroxylum seeds, has been proven to promote bone formation of bone marrow stem cells. However, the effect of chrysin on osteogenic differentiation of DPSCs remains unclear. This study aimed to investigate the role of Chrysin in promoting osteogenic differentiation of DPSCs and in DPSC-based bone formation.

MATERIAL AND METHODS

We investigated the effects of chrysin on DPSCs from patients by CCK-8 assay, Alizarin Red S staining, qPCR and Western blotting. The effects of chrysin on DPSC-based bone formation in a heterotopic osteogenesis model in nude mice and a rat calvarial defect model were also performed. Finally, we investigated the mechanism of chrysin-treated DPSCs by proteomics.

RESULTS

Chrysin upregulated the expression of osteogenic proteins and induced osteogenic differentiation of DPSCs. Moreover, chrysin induced abundant β-TCP-induced formation of mineralized bone tissue and promoted DPSC-based bone formation in a heterotopic osteogenesis model in nude mice and a rat calvarial defect model. Proteomics showed that upregulation of the Smad3 was closely related to osteogenic differentiation. Inhibiting of Smad3 activation by a Smad3 inhibitor could reverse the chrysin-mediated increases in the expression levels of osteogenic genes and osteogenic induction of DPSCs.

CONCLUSIONS

Our study implies the intriguing potential of chrysin-treated DPSCs in bone regeneration and bone defect repair.

Structurally characterized gallium-chrysin complexes with anticancer potential

Chemotherapeutic metal-based compounds are effective anticancer agents; however, their cytotoxic profile and significant side effects limit their wide application. Natural products, especially flavonoids, are a prominent alternative source of anticancer agents that can be used as ligands for the generation of new bioactive complexes with metal ions of known biochemical and pharmacological activities. Herein, we present the synthesis and detailed structural and physicochemical characterizations of three novel complex assemblies of Ga(iii) with the flavonoid chrysin and the ancillary aromatic chelators 1,10-phenanthroline, 2,2'-bipyridine and imidazole. The complexes constitute the only crystallographically characterized structures having a metal core from the boron group elements and a flavonoid as the ligand. The in vitro biological evaluation of the three complexes in a series of cancer cell lines of different origin established their cytotoxicity and ROS generating potential. In particular, the Ga(iii)-chrysin-imidazole complex displayed the highest anticancer efficacy against all cancer cell lines with IC50 values in the low micromolar range (<1.18 μM), a result worth further investigation.

Response surface method was used to optimize the ultrasonic assisted extraction of flavonoids from Crinum asiaticum

In this study, ultrasound-assisted extraction of flavonoid from Crinum asiaticum was studied through response surface methodology (RSM) to gain the best extraction process of flavonoid and enhance the extraction rate of flavonoid. In the following RSM experiment, we selected the corresponding data of every factor as the center point through the single-factor experiments, then the experimental data was subjected to multiple regression analysis. According to the statistical analysis results, the results were consistent with the polynomial regression model, the determination coefficient (R2) was 0.9769. The best conditions for maximum flavonoid yield were 60% ethanol concentration, 64 °C for extraction temperature, 1:28 (v/w) solid-to-liquid ratio with extraction time for 47 min. The best response of flavonoid yield was 1.63972%. The predicted results for best reaction conditions were in good agreement with experiment values. Ultrasound-assisted extraction method can enhance the extraction rate of flavonoid significantly. It is a powerful tool to extract of important phytochemicals from nature plant.

Nanoscale modification of chrysin for improved of therapeutic efficiency and cytotoxicity

Chrysin, as a flavone, is a promising drug candidate because of its multifaceted properties, such as anti-inflammatory, antioxidant and anticancer. However, its poor bioavailability is a bottleneck for pharmaceutical applications. To enhance the bioactive effects, chrysin-loaded poly (D,L-lactic-co-glycolic acid) and polyvinyl alcohol were successfully prepared to overcome problems associated with chrysin. The properties of modified nanochrysin were analysed by in vitro dissolution study, XRD, FTIR and SEM. Free radical scavenging potentials of the modified nanochrysin against DPPH were confirmed based on its stable antioxidant effects. A DNA instability enhancement was observed after H₂O₂ exposure, whereas chrysin decreased the H₂O₂ activity, and modified nanochrysin was more potent in this regard. Blood compatibility on red blood cells was confirmed by haemolytic and in vitro cytotoxicity assays. The in vitro anticancer activity of the modified nanochrysin towards MCF-7 and SKOV-3 cell lines using various parameters was investigated. The nanochrysin was found to exert cell growth arrest against both cancer cells in a dose-dependent manner. IC₅₀ value was significantly decreased in nanochrysin in comparison with pure chrysin and induced apoptotic cell death pathway. The results of this study suggest that the nanochrysin might be used for medical applications and offer a beneficial formulation for chemotherapy.

Potentiation of luteolin cytotoxicity by flavonols fisetin and quercetin in human chronic lymphocytic leukemia cell lines

Despite numerous studies chronic lymphocytic leukemia (CLL) still remains an incurable disease. Therefore, all new compounds and novel strategies which are able to eradicate CLL cells should be considered as valuable clues for a potential future remedy against this malignancy. In the present study, the cytotoxic profiles of natural flavonoids were described in two human CLL cell lines, HG-3 and EHEB, indicating the flavone luteolin as the most potent flavonoid with half-maximal inhibitory constants (IC50) of 37 μM and 26 μM, respectively. Luteolin significantly increased the apoptotic cell population in both cell lines by increasing the activities of caspases-3 and -9 and triggering the intrinsic apoptotic pathway. Two flavonols, fisetin and quercetin, were somewhat less efficient in suppressing cellular viability, whereas baicalein, chrysin, (+)-catechin and hesperetin exerted only a small or no response at doses as high as 100 μM. Both fisetin and quercetin were able to augment the cytotoxic activity of luteolin in both cell lines by reducing the IC50 values up to four fold. As a result of this, luteolin displayed cytotoxicity activity already at low micromolar concentrations that could potentially be physiologically achievable through oral ingestion. No other tested flavonoids were capable of sensitizing CLL cells to luteolin pointing to a specific binding of fisetin and quercetin to the cellular targets which interfere with the signaling pathways induced by luteolin. Although further molecular studies to unravel this potentiating mechanism are certainly needed, this phenomenon could contribute to future remedies for prevention and treatment of chronic lymphocytic leukemia.

Preparation and Evaluation of Chrysin Encapsulated in PLGA- PEG Nanoparticles in the T47-D Breast Cancer Cell Line

BACKGROUND

Polymeric nanoparticles are attractive materials that have been widely used in medicine for drug delivery, with therapeutic applications. In our study, polymeric nanoparticles and the anticancer drug, chrysin, were encapsulated into poly (D, L-lactic-co-glycolic acid) poly (ethylene glycol) (PLGA-PEG) nanoparticles for local treatment.

MATERIALS AND METHODS

PLGA: PEG triblock copolymers were synthesized by ring-opening polymerization of D, L-lactide and glycolide as an initiator. The bulk properties of these copolymers were characterized using 1H nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. In addition, the resulting particles were characterized by scanning electron microscopy.

RESULTS

The chrysin encapsulation efficiency achieved for polymeric nanoparticles was 70% control of release kinetics. The cytotoxicity of different concentration of pure chrysin and chrysin loaded in PLGA-PEG (5-640μM) on T47-D breast cancer cell line was analyzed by MTT-assay.

CONCLUSIONS

There is potential for use of these nanoparticles for biomedical applications. Future work should include in vivo investigation of the targeting capability and effectiveness of these nanoparticles in the treatment of breast cancer.