Arbutin suppresses osteosarcoma progression via miR-338-3p/MTHFD1L and inactivation of the AKT/mTOR pathway

Comparison of the effects of β-Arbutin on the NF-κB pathway in two-dimensional (2D) and three-dimensional (3D) colorectal cancer cell lines

Colorectal cancer (CRC) ranks as the third most prevalent cancer worldwide and is associated with significant mortality, primarily due to metastatic spread and resistance to therapy. In approximately half of CRC cases, the NF-κB signaling pathway is dysregulated, contributing to tumor progression, cell survival, and invasive behavior. β-Arbutin, a natural β-glucoside compound, has demonstrated potential anticancer activity. This study investigated the suppressive impact of β-Arbutin on NF-κB signaling in CRC, utilizing both conventional 2D and advanced 3D cell culture systems. HT-29 colorectal cancer cells were grown using both two-dimensional (2D) monolayer cultures and three-dimensional (3D) alginate bead models. Cell viability was assessed via WST-1 assay to establish the half-maximal inhibitory concentration (IC50) values for β-Arbutin and the reference drug Sulfasalazine. Flow cytometry was employed to quantify apoptotic cell populations, Caspase 3/7 enzymatic activity, and related protein expression. Immunofluorescence staining further validated the protein levels detected by flow cytometry. All data were statistically analyzed using GraphPad Prism software, with a p-value threshold of <0.05 considered significant. β-Arbutin exhibited a more pronounced reduction in cell viability in 3D culture systems compared to conventional 2D cultures. The compound induced significantly higher apoptosis rates in 3D models (56.46 %) versus 2D cultures (22.11 %; p < 0.0001). Similarly, Caspase 3/7 activity was markedly elevated in β-Arbutin-treated 3D cells (53.56 %) relative to their 2D counterparts (34.04 %; p < 0.0001). Furthermore, β-Arbutin treatment resulted in a more substantial decrease in target protein expression levels in 3D cultures compared to 2D systems. The 3D CRC models demonstrated significantly greater sensitivity to β-Arbutin than 2D cultures, with more robust NF-κB pathway suppression and apoptotic response. This differential efficacy underscores the superior biomimetic properties of 3D culture systems. Our results position β-Arbutin as a potent NF-κB-targeting agent and validate its potential for clinical translation in colorectal cancer therapy.

Role of arbutin in the inhibition of FBXO5 in hepatocellular carcinoma

PURPOSE

This work investigated the effect of FBXO5 in hepatocellular carcinoma (HCC) and the mechanism of action of arbutin in its inhibition.

METHODS

FBXO5 mRNA and protein expressions in the tumor were assessed using TCGA, ICGC and HPA databases. Cox regression analysis and Kaplan-Meier survival curves were employed to assess the impact of FBXO5 on the survival outcomes of patients with HCC. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA), and Gene Set Variation Analysis (GSVA) were used to investigate the biological function associated with FBXO5-related genes. The role of FBXO5 as oncogene and the inhibitory mechanism of arbutin were confirmed through western blotting (WB), reverse transcription quantitative polymerase chain reaction (RT-qPCR), and in vitro experiments such as scratch wound-healing migration assay, plate clone formation assay, and transwell migration assay.

RESULTS

Patients with high FBXO5 expression showed shorted overall survival (OS), progression-free survival (PFS), disease-specific survival (DSS), and disease-free survival (DFS). FBXO5 was identified as an independent prognostic risk factor associated with the cell cycle. In vitro investigations indicated that FBXO5 facilitated HCC progression by modulating the cell cycle, while arbutin suppressed FBXO5 expression and regulated cell cycle dynamics.

CONCLUSION

FBXO5 is a potential diagnostic and prognostic biomarker for HCC, and arbutin may exert anticancer effects through the suppression of FBXO5 expression.

Pharmacological and biochemical insights into lead-induced hepatotoxicity: Pathway interplay and the protective effects of arbutin via the oral and intraperitoneal routes in silico and in vivo

INTRODUCTION

Lead acetate (PbAc), a hazardous heavy metal, poses significant threats to human health and the environment because of widespread industrial exposure. PbAc exposure leads to liver injury primarily through oxidative stress and the disruption of key regulatory pathways. Understanding these mechanisms and exploring protective agents are vital for mitigating PbAc-induced hepatotoxicity. Therefore, we aimed to investigate the molecular pathways implicated in PbAc-induced liver damage, focusing on Sirt-1, Nrf2 (HO-1, NQO1, and SOD), Akt-1/GSK3β, m-TOR, and P53. Additionally, we aimed to assess the hepatoprotective effects of arbutin, which is administered orally and intraperitoneally, to determine the most effective delivery method.

METHODOLOGY

In silico analyses were conducted to identify relevant protein networks associated with Sirt-1 and AKT-1/GSK-3B pathways. The pharmacodynamic properties of arbutin were examined, followed by molecular docking studies to elucidate its interactions with the selected protein network. In vivo preclinical studies were carried out on adult male rats randomly assigned to 6 different treatment groups, including PbAc exposure and PbAc exposure treated with arbutin either orally or intraperitoneally.

RESULTS

PbAc exposure led to hepatic oxidative stress, as evidenced by elevated MDA levels and SIRT-1 inhibition, disrupting antioxidant pathways and activating antiautophagic and proapoptotic pathways, ultimately resulting in hepatocyte necrosis. Both oral and intraperitoneal arbutin administration effectively modifed these effects, with intraperitoneal delivery showing superior efficacy in mitigating PbAc-induced histological, immunological, and biochemical alterations.

CONCLUSION

This study provides insights into the molecular mechanisms underlying PbAc-induced liver injury and highlights the hepatoprotective potential of arbutin. These findings suggest that arbutin, particularly when administered intraperitoneally, holds promise as a therapeutic agent for combating PbAc-induced hepatotoxicity.

Arbutin overcomes tumor immune tolerance by inhibiting tumor programmed cell death-ligand 1 expression

Arbutin, predominantly derived from the bearberry plant, exhibits promising immunomodulatory properties. Given its ability to influence the programmed cell death-ligand 1/ programmed cell death-1 (PD-L1/PD-1) pathway, it is emerging as a potential alternative treatment for cancer. A reduced expression of PD-L1, as seen after arbutin treatment, can bolster immune responses critical step in effective tumor immunotherapy. However, the molecular mechanism by which arbutin inhibits PD-L1 is still incompletely known. The expression of PD-L1 was decreased after tumor cells were treated with arbutin. Arbutin can downregulate the expression of PD-L1 on the cell surface via the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway. The findings suggest the protective role of arbutin and provide novel insights into immunotherapy, which involves inhibiting the AKT/mTOR signaling pathway. Arbutin might serve as a potential therapeutic agent alone or in combination with other treatments.

Molecular analysis of dUTPase of Helicobacter pylori for identification of novel inhibitors using in silico studies

The human gastric pathogen Helicobacter pylori chronically affects the gastric mucosal layer of approximately half of world's population. The emergence of resistant strains urges the need for identification of novel and selective drug against new molecular targets. A ubiquitous enzyme, Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase), is considered as first line of defense against uracil mis-incorporation into DNA, and essential for genome integrity. Lack of dUTPase triggers an elevated recombination frequency, DNA breaks and ultimately cell death. Hence, dUTPase can be considered as a promising target for development of novel lead inhibitor compounds in H. pylori treatment. Herein, we report the generation of three-dimensional model of the target protein using comparative modelling and its validation. To identify dUTPase inhibitors, a high throughput virtual screening approach utilizing Knowledge-based inhibitors and DrugBank database was implemented. Top ranked compounds were scrutinized based on investigations of the protein-ligand interaction fingerprints, molecular interaction maps and binding affinities and the drug potentiality. The best ligands were studied further for complex stability and intermolecular interaction profiling with respect to time under 100 ns classical molecular dynamic stimulation, establishing significant stability in dynamic states as observed from RMSD and RMSF parameters and interactions with the catalytic site residues. The binding free energy calculation computed using MM-GBSA method from the MD simulation trajectories demonstrated that our molecules possess strong binding affinity towards the Helicobacter pylori dUTPase protein. We conclude that our proposed molecules may be potential lead molecules for effective inhibition against the H. pylori dUTPase protein subject to experimental validation.Communicated by Ramaswamy H. Sarma.

Determination of arbutin in vitro and in vivo by LC-MS/MS: Pre-clinical evaluation of natural product arbutin for its early medicinal properties

ETHNOPHARMACOLOGICAL RELEVANCE

Arbutin is a naturally occurring glucoside extracted from plants, known for its antioxidant and tyrosinase inhibiting properties. It is widely used in cosmetic and pharmaceutical industries. With in-depth study of arbutin, its application in disease treatment is expanding, presenting promising development prospects. However, reports on the metabolic stability, plasma protein binding rate, and pharmacokinetic properties of arbutin are scarce.

AIM OF THE STUDY

The aim of this study is to enrich the data of metabolic stability and pharmacokinetics of arbutin through the early pre-clinical evaluation, thereby providing some experimental basis for advancing arbutin into clinical research.

MATERIALS AND METHODS

We developed an efficient and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for determining arbutin in plasma. We investigated the metabolic and pharmacokinetic properties of arbutin through in vitro metabolism assay, cytochrome enzymes P450 (CYP450) inhibition studies, plasma protein binding rate analysis, Caco-2 cell permeability tests, and rat pharmacokinetics to understand its in vivo performance.

RESULTS

In vitro studies show that arbutin is stable, albeit with some species differences. It exhibits low plasma protein binding (35.35 ± 11.03% ∼ 40.25 ± 2.47%), low lipophilicity, low permeability, short half-life (0.42 ± 0.30 h) and high oral bioavailability (65 ± 11.6%). Arbutin is primarily found in the liver and kidneys and is eliminated in the urine. It does not significantly inhibit CYP450 up to 10 μM, suggesting a low potential for drug interactions. Futhermore, preliminary toxicological experiments indicate arbutin's safety, supporting its potential as a therapeutic agent.

CONCLUSION

This study provides a comprehensive analysis the drug metabolism and pharmacokinetics (DMPK) of arbutin, enriching our understanding of its metabolism stability and pharmacokinetics properties, It establishes a foundation for further structural optimization, pharmacological studies, and the clinical development of arbutin.

Deciphering chemoresistance in osteosarcoma: Unveiling regulatory mechanisms and function through the lens of noncoding RNA

Osteosarcoma (OS) is a primary malignant bone tumor and is prevalent in children, adolescents, and elderly individuals. It has the characteristics of high invasion and metastasis. Neoadjuvant chemotherapy combined with surgical resection is the most commonly used treatment for OS. However, the efficacy of OS is considerably diminished by chemotherapy resistance. In recent years, noncoding RNAs (ncRNAs), including microRNAs, long noncoding RNAs, and circular RNAs, are hot topics in the field of chemotherapy resistance research. Several studies have demonstrated that ncRNAs are substantially associated with chemoresistance in OS. Thus, the present study overviews the abnormally expressed ncRNAs in OS and the molecular mechanisms involved in chemoresistance, with an emphasis on their function in promoting or inhibiting chemoresistance. ncRNAs are expected to become potential therapeutic targets for overcoming drug resistance and predictive biomarkers in OS, which are of great significance for enhancing the therapeutic effect and improving the prognosis.

Reprogramming of glucose metabolism: Metabolic alterations in the progression of osteosarcoma

Metabolic reprogramming is an adaptive response of tumour cells under hypoxia and low nutrition conditions. There is increasing evidence that glucose metabolism reprogramming can regulate the growth and metastasis of osteosarcoma (OS). Reprogramming in the progress of OS can bring opportunities for early diagnosis and treatment of OS. Previous research mainly focused on the glycolytic pathway of glucose metabolism, often neglecting the tricarboxylic acid cycle and pentose phosphate pathway. However, the tricarboxylic acid cycle and pentose phosphate pathway of glucose metabolism are also involved in the progression of OS and are closely related to this disease. The research on glucose metabolism in OS has not yet been summarized. In this review, we discuss the abnormal expression of key molecules related to glucose metabolism in OS and summarize the glucose metabolism related signaling pathways involved in the occurrence and development of OS. In addition, we discuss some of the targeted drugs that regulate glucose metabolism pathways, which can lead to effective strategies for targeted treatment of OS.

A spotlight on the interplay of signaling pathways and the role of miRNAs in osteosarcoma pathogenesis and therapeutic resistance

Osteosarcoma (OS) is one of the most common bone cancers that constantly affects children, teenagers, and young adults. Numerous epigenetic elements, such as miRNAs, have been shown to influence OS features like progression, initiation, angiogenesis, and treatment resistance. The expression of numerous genes implicated in OS pathogenesis might be regulated by miRNAs. This effect is ascribed to miRNAs' roles in the invasion, angiogenesis, metastasis, proliferation, cell cycle, and apoptosis. Important OS-related mechanistic networks like the WNT/b-catenin signaling, PTEN/AKT/mTOR axis, and KRAS mutations are also affected by miRNAs. In addition to pathophysiology, miRNAs may influence how the OS reacts to therapies like radiotherapy and chemotherapy. With a focus on how miRNAs affect OS signaling pathways, this review seeks to show how miRNAs and OS are related.

Arbutin: Occurrence in Plants, and Its Potential as an Anticancer Agent

Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the plants of the Asteraceae, Ericaceae, Proteaceae and Rosaceae families. It is one of the most widely used natural skin-whitening agents. In addition to its skin whitening property, arbutin possesses other therapeutically relevant biological properties, e.g., antioxidant, antimicrobial and anti-inflammatory, as well as anticancer potential. This review presents, for the first time, a comprehensive overview of the distribution of arbutin in the plant kingdom and critically appraises its therapeutic potential as an anticancer agent based on the literature published until the end of August 2022, accessed via several databases, e.g., Web of Science, Science Direct, Dictionary of Natural Products, PubMed and Google Scholar. The keywords used in the search were arbutin, cancer, anticancer, distribution and hydroquinone. Published outputs suggest that arbutin has potential anticancer properties against bladder, bone, brain, breast, cervix, colon, liver, prostate and skin cancers and a low level of acute or chronic toxicity.

Silencing of lncRNA KLF3-AS1 represses cell growth in osteosarcoma via miR-338-3p/MEF2C axis

BACKGROUND

Osteosarcoma (OS) is a highly recurrent malignancy occurring among adolescents. The goal of this research was to scrutinize the role and action mechanism of KLF3-AS1 in OS.

METHODS

Western blotting and quantitative reverse transcription real-time PCR were conducted to ascertain the mRNA expressions of miR-338-3p, KLF3-AS1, and MEF2C in OS cell lines and tissue samples. Colony formation and CCK-8 experiments were done to evaluate the proliferative capacity of the cells. Western blotting was also executed to measure the relative expressions of the proteins Bcl-2 and Bax. RNA immunoprecipitation and dual luciferase reporter experiments were carried out to validate the target relationships among MEF2C, KLF3-AS1, and miR-338-3p. Mouse xenograft models were created to assess the influences of KLF3-AS1 on the growth of tumors in vivo.

RESULTS

Elevated levels of KLF3-AS1 and MEF2C and reduced amounts of miR-338-3p were identified in OS. KLF3-AS1 targeted miR-338-3p, and miR-338-3p further targeted MEF2C. Silencing KLF3-AS1 induced apoptosis and attenuated proliferation in vitro and repressed the tumor growth in vivo. Inhibiting miR-338-3p inverted the cancer-suppressing effects of KLF3-AS1 silencing. Meanwhile, loss of MEF2C partially eliminated the effects brought about by miR-338-3p downregulation, namely the stimulation of cell growth and suppression of apoptosis.

CONCLUSIONS

Silencing of KLF3-AS1 could repress the growth of cells and induce apoptosis by regulating miR-338-3p/MEF2C in OS. This suggests that the regulatory axis KLF3-AS1/miR-338-3p/MEF2C is a prospective target for OS treatment.

S100 calcium-binding protein A10 contributes to malignant traits in osteosarcoma cells by regulating glycolytic metabolism via the AKT/mTOR pathway

As an aggressive musculoskeletal malignancy, osteosarcoma (OSa) is popular among young adults and teenagers worldwide. S100 calcium-binding protein A10 (S100A10) functioned as a novel tumor-promoting protein in several human cancers. However, its role in OSa remains obscure. In this study, gene and protein levels were respectively determined by RT-qPCR or Western blotting. OSa cell proliferation, apoptosis, and metastasis were evaluated via CCK-8, colony formation, flow cytometry, and Transwell assays. To assess the glycolysis level, glucose consumption and lactate production were detected. It was found S100A10 was highly expressed in OSa tissues and cell lines. Besides, S100A10 facilitated proliferation and metastasis, and inhibited apoptosis in OSa cells. In addition, S100A10 regulated OSa cell proliferation, metastasis and apoptosis via mediating the glycolysis process. Furthermore, S100A10-mediated AKT/mTOR signaling accelerated glycolysis, thereby promoting malignant behaviors in OSa cells. Taken together, our findings indicated that S100A10 might promote malignant phenotypes of OSa cells by accelerating glycolysis and activating the AKT/mTOR signaling, providing a promising target for OSa treatment.

Estrogen Receptor-α Suppresses Liver Carcinogenesis and Establishes Sex-Specific Gene Expression

Estrogen protects females from hepatocellular carcinoma (HCC). To determine whether this protection is mediated by classic estrogen receptors, we tested HCC susceptibility in estrogen receptor-deficient mice. In contrast to a previous study, we found that diethylnitrosamine induces hepatocarcinogenesis to a significantly greater extent when females lack Esr1, which encodes Estrogen Receptor-α. Relative to wild-type littermates, Esr1 knockout females developed 9-fold more tumors. Deficiency of Esr2, which encodes Estrogen Receptor-β, did not affect liver carcinogenesis in females. Using microarrays and QPCR to examine estrogen receptor effects on hepatic gene expression patterns, we found that germline Esr1 deficiency resulted in the masculinization of gene expression in the female liver. Six of the most dysregulated genes have previously been implicated in HCC. In contrast, Esr1 deletion specifically in hepatocytes of Esr1 conditional null female mice (in which Cre was expressed from the albumin promoter) resulted in the maintenance of female-specific liver gene expression. Wild-type adult females lacking ovarian estrogen due to ovariectomy, which is known to make females susceptible to HCC, also maintained female-specific expression in the liver of females. These studies indicate that Esr1 mediates liver cancer risk, and its control of sex-specific liver gene expression involves cells other than hepatocytes.

A comprehensive review of the therapeutic potential of α-arbutin

Cosmetic dermatology preparations such as bleaching agents are ingredients with skin-related biological activities for increasing and improving skin beauty. The possibility of controlling skin hyperpigmentation disorders is one of the most important research goals in cosmetic preparations. Recently, cosmetics containing herbal and botanical ingredients have attracted many interests for consumers of cosmetic products because these preparations are found safer than other preparations with synthetic components. However, high-quality trial studies in larger samples are needed to confirm safety and clinical efficacy of phytotherapeutic agents with high therapeutic index. Arbutin (p-hydroxyphenyl-β-d-glucopyranoside) is a bioactive hydrophilic polyphenol with two isomers including alpha-arbutin (4-hydroxyphenyl-α-glucopyranoside) and β-arbutin (4-hydroxyphenyl-β-glucopyranoside). It is used as a medicinal plant in phytopharmacy. Studies have shown that alpha-arbutin is 10 times more effective than natural arbutin. A comparison of IC50 values showed that α-arbutin (with concentration 2.0 mM) has a more potent inhibitory activity on human tyrosinase against natural arbutin (with higher concentration than 30 mM). A review of recent studies showed that arbutin could be beneficial in treatment of various diseases such as hyperpigmentation disorders, types of cancers, central nervous system disorders, osteoporosis, diabetes, etc. This study was designed to describe the therapeutic efficiencies of arbutin.