Gambogic Acid Inhibits the Progression of Gastric Cancer via circRNA_ASAP2/miR-33a-5p/CDK7 Axis

Multi-spectroscopic and in silico investigation of gambogic acid-calf thymus DNA interactions

Gambogic acid (GA), a xanthanoid compound, is derived from Garcinia Hanbury gamboge resin. Studying GA's DNA binding and targeting processes is crucial to understanding its tumor-targeting potentiality. This study used spectroscopic and in silico methods to investigate the GA-calf thymus DNA-binding interaction. The results of the UV-visible absorbance spectroscopy revealed that GA binds to DNA and forms a complex. Investigation of fluorescence quenching using ethidium bromide-DNA revealed that GA displaced ethidium bromide, and the type of quenching was static in nature, as determined by Stern-Volmer plot data. Thermodynamic analysis of the DNA-GA complex revealed a spontaneous, favorable interaction involving hydrogen bonding and hydrophobic interactions. Quenching experiments with potassium iodide, Acridine orange, and NaCl verified GA's groove-binding nature and the presence of weak electrostatic interactions. The thermal melting temperature of DNA in its native and bound states with GA did not differ significantly (69.27° C to 71.25° C), validating the binding of GA to the groove region. Furthermore, the groove-binding nature of GA was confirmed by studying its interaction with ssDNA and DNA viscosity. The methods of DSC, FT-IR, and CD spectroscopy have not revealed any structural aberrations in DNA bound with GA. Molecular docking and modeling studies revealed that GA has a groove-binding nature with DNA, which is consistent with prior experimental results. Finally, the findings shed information by which GA attaches to DNA and provide insights into its recognized anticancer effects via topoisomerase inhibition causing DNA cleavage, inhibition of cell proliferation and apoptosis.Communicated by Ramaswamy H. Sarma.

Emerging tendencies for the nano-delivery of gambogic acid: a promising approach in oncotherapy

Despite the advancements in cancer therapies during the past few years, chemo/photo resistance, severe toxic effects, recurrence of metastatic tumors, and non-selective targeting remain incomprehensible. Thus, much effort has been spent exploring natural anticancer compounds endowed with biosafety and high effectiveness in cancer prevention and therapy. Gambogic acid (GA) is a promising natural compound in cancer therapy. It is the major xanthone component of the dry resin extracted from the Garcinia hanburyi Hook. f. tree. GA has significant antiproliferative effects on different types of cancer, and it exerts its anticancer activities through various pathways. Nonetheless, the clinical translation of GA has been hampered, partly due to its water insolubility, low bioavailability, poor pharmacokinetics, rapid plasma clearance, early degradation in blood circulation, and detrimental vascular irritation. Lately, procedures have been invented demonstrating the ability of nanoparticles to overcome the challenges associated with the clinical use of natural compounds both in vitro and in vivo. This review sheds light on the recent emerging trends for the nanodelivery of GA to cancer cells. To the best of our knowledge, no similar recent review described the different nanoformulations designed to improve the anticancer therapeutic activity and targeting ability of GA.

Nano-Drug Delivery Systems Based on Natural Products

Natural products have proven to have significant curative effects and are increasingly considered as potential candidates for clinical prevention, diagnosis, and treatment. Compared with synthetic drugs, natural products not only have diverse structures but also exhibit a range of biological activities against different disease states and molecular targets, making them attractive for development in the field of medicine. Despite advancements in the use of natural products for clinical purposes, there remain obstacles that hinder their full potential. These challenges include issues such as limited solubility and stability when administered orally, as well as short durations of effectiveness. To address these concerns, nano-drug delivery systems have emerged as a promising solution to overcome the barriers faced in the clinical application of natural products. These systems offer notable advantages, such as a large specific surface area, enhanced targeting capabilities, and the ability to achieve sustained and controlled release. Extensive in vitro and in vivo studies have provided further evidence supporting the efficacy and safety of nanoparticle-based systems in delivering natural products in preclinical disease models. This review describes the limitations of natural product applications and the current status of natural products combined with nanotechnology. The latest advances in nano-drug delivery systems for delivery of natural products are considered from three aspects: connecting targeting warheads, self-assembly, and co-delivery. Finally, the challenges faced in the clinical translation of nano-drugs are discussed.

Therapeutic effect and metabolic fingerprinting of triple-negative breast cancer cells following exposure to a novel pH-responsive, gambogic acid-loaded micelle

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis and lacks effective therapeutic targets. The use of gambogic acid (GA), a class of active ingredients in traditional Chinese medicine with anti-tumour potential, is limited in tumour therapy owing to its drawbacks and unclear organ toxicity. In this study, we used the pH-responsive amphiphilic block copolymer, PEOz-PCL, to create nanodrugs for GA delivery to MDA-MB-231 cells. The pH-responsive GA-loaded micelles were prepared through nanoprecipitation with a more homogeneous size. The average particle size was 42.29 ± 1.74 nm, and the zeta potential value was 9.88 ± 0.17 mV. The encapsulation rate was 85.06%, and the drug loading rate was 10.63%. The process was reproducible, and sustained release reached 80% in 96 h at acid pH 5.0. Furthermore, cellular tests using CCK-8, TUNEL, and flow cytometry revealed that pH-responsive GA-loaded micelles killed MDA-MB-231 cells more effectively and had much higher activity and targeting compared with free drugs. Metabolomic analysis of the changes in differential metabolites revealed that pH-responsive GA-loaded micelles may inhibit TNBC cells by causing amino acid anabolism, nucleotide metabolism, and glucose metabolism, as well as by affecting their energy sources. The study outcomes will help understand the mechanism of action and the therapeutic efficacy of pH-responsive GA-loaded micellesin vivo.

MiR-1275 Targeting SPARC Promotes Gambogic Acid-Induced Inhibition of Gastric Cancer

Gambogic acid (GA) has been observed to effectively impede the progression of numerous types of cancers. In this study, we investigated the effects of miR-1275 and Secreted Protein Acidic and Cysteine Rich (SPARC) on GA in gastric cancer (GC). miR-1275 and SPARC expression were determined in GC cell lines and tissues using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The correlation between miR-1275 and SPARC expression was ascertained using Pearson's correlation coefficient. Cell proliferation was assessed using the cell counting kit-8 (CCK-8) assay. The Transwell assay was conducted to examine cell migration. A dual-luciferase reporter assay was used to verify the regulatory relationship between miR-1275 and SPARC. The levels of SPARC, Bcl-2, and Bax proteins were estimated using western blotting. To verify the effects of GA on the growth of GC cells in vivo, a tumorigenesis experiment was performed in nude mice. GA suppressed GC cell viability and migration, facilitated apoptosis, and inhibited tumor growth in vivo and in vitro. Low levels of miR-1275 been observed in GC cell lines and tissues. GA-treated GC cells manifested high miR-1275 levels. In functional experiments, miR-1275 enhanced the influence of GA on cell apoptosis, migration, and proliferation. Furthermore, GA treatment suppressed SPARC upregulation in GC cell lines and tissues. Pearson's correlation coefficient revealed that miR-1275 expression negatively correlated with SPARC expression. Mechanistically, miR-1275 promoted growth inhibition in GA-treated GC cells by targeting SPARC. Our study indicates that miR-1275 enhances the suppressive effect of GA on GC progression by inhibiting SPARC expression. Through this study, we contribute to the knowledge of a new mechanism by which GA suppresses GC progression.

Gambogic Acid Inhibits Gastric Cancer Cell Proliferation through Necroptosis

Gambogic acid (GA) is a natural xanthonoid secreted by Garcinia hanburyi tree. It possesses anti-cancer activity in various types of cancers. In gastric cancer, it inhibits cell proliferation through increasing apoptosis. However, whether necroptosis is involved in the GA-induced proliferation inhibited in gastric cancer is unknown. In the present study, we found that RIPK1 specific inhibitor necrostatin-1 (Nec-1) attenuated GA-induced proliferation inhibition. GA treatment increased the phosphorylation of necroptosis-related proteins, RIPK1, RIPK3, and MLKL, and their interactions to form the necrosome complex. The effector protein Drp-1 was dephosphorylated by GA treatment. Inhibition of necroptosis by different inhibitors and PGAM5 knockdown attenuated GA-induced cell death in gastric cancer cell lines, thereby attenuating GA-caused cell proliferation inhibition. All the data supported the conclusion that GA could inhibit gastric cancer cell proliferation by inducing necroptosis.

Impact of pri-let-7a-1 rs10739971 for Gastric Cancer Predisposition in an Amazon Region

Gastric cancer (GC) is the fifth most common type of cancer and the fourth leading cause of cancer death. In Brazil, GC has a high incidence and mortality rates, and it is highly variable by region. The Amazon region has significant rising rates among all Brazil regions. Only very few studies have evaluated the association between genetic variants and the risk of gastric cancer in the Brazilian Amazon population. Therefore, this study aimed to investigate associations between single nucleotide polymorphisms of miRNA processing genes and the risk for GC in this population. Potentially functional single nucleotide polymorphisms from miRNA processing genes were genotyped in 159 cases and 193 healthy controls by QuantStudio Real Time PCR. According to our findings, the genotype GG of the variant rs10739971 presents a lower risk to the development of GC in comparison to the remaining genotypes (p = 0.000016; OR = 0.055; 95% CI = 0.015-0.206). This is the first study to report the association of pri-let-7a-1 rs10739971 with GC in the Brazilian Amazon population, which is a highly mixed population with a unique genetic constitution that is different from other populations that are studied in the vast majority of scientific research.

Circular RNA Controls Tumor Occurrence and Development via Cell Cycle Regulation

Circular RNAs (circRNAs) participate in the occurrence and development of various diseases through different mechanisms, such as by acting as a microRNA (miRNA) sponge, interacting with RNA-binding proteins, and regulating gene transcription and protein translation. For example, the abnormal expression of specific circRNAs in tumor cells can alter key regulatory factors and the cell cycle network, resulting in cell cycle disorders and the development and metastasis of tumors. Here, we summarize the mechanisms involved in the circRNA-mediated processes that lead to uncontrolled cell cycle and tumor cell proliferation. Extensive studies investigating the abnormal expression of circRNAs in different cancer types have been conducted. The unique characteristics of circRNAs and their ability to regulate the cell cycle through diverse mechanisms is extremely valuable in tumor diagnosis, treatment, and prognosis. Our review may assist in further understanding the circRNA-mediated regulation of the cell cycle in tumors and provide insights for research on circRNA-based therapeutic strategies and biological diagnosis for cancer.

miR-33a-5p Targets RAP2A to Mediate the Sensitivity of Gastric Cancer Cells to 5-FU

Objective. The objective of this study is to explore the effects of microRNA-33a-5p (miR-33a-5p)-ras-related protein Rap-2a (RAP2A) on biological functions of gastric cancer (GC) and to find the potential functional mechanism. Methods. We measured the miR-33a-5p expression in 30 GC tissues and cellular level and 30 adjacent normal tissues as control. Besides, the expression of miR-33a-5p was checked at cell level as well. To screen the possible targets of miR-33a-5p, prediction software was used and gene RAP2A attracted our attention. Through a series of experiments including real-time polymerase chain reaction (qRT-PCR), luciferase assay, and western blotting (WB), we verified RAP2A as a potential target of miR-33a-5p. The impacts of miR-33a-5p and RAP2A on biological functions of GC cell lines (BGC-823 and MGC-803) were analyzed by subsequent experiments. Cell invasion was tested by invasion assays. Cell proliferation was measured by cell counting kit-8 (CCK-8) assay. Cell clone was measured by clone formation assays. Finally, the expression of RAP2A protein was analyzed by WB assay. Results. We found miR-33a-5p was expressed lowly in GC tissues and cells. Overexpression of miR-33a-5p in BGC-823 and MGC-803 cells greatly inhibited the cell invasion and colony number. Furthermore, compared to sh-control (shControl), RAP2A knockdown (sh-RAP2A/shRAP2A) raised the sensitivity of GC cells to 5-FU significantly, characterized as reducing cell apoptosis. Conclusions. The expression of miR-33a-5p was lower in GC cell lines and tissues obviously, indicating that miR-33a-5p served as the antitumor gene in GC. The expression of RAP2A regulated negatively the sensitivity of GC cells to 5-FU. According to our in vitro experiments, miR-33a-5p/RAP2A was likely to become a new therapeutic target for GC.

Role of Plant-Derived Active Constituents in Cancer Treatment and Their Mechanisms of Action

Despite significant technological advancements in conventional therapies, cancer remains one of the main causes of death worldwide. Although substantial progress has been made in the control and treatment of cancer, several limitations still exist, and there is scope for further advancements. Several adverse effects are associated with modern chemotherapy that hinder cancer treatment and lead to other critical disorders. Since ancient times, plant-based medicines have been employed in clinical practice and have yielded good results with few side effects. The modern research system and advanced screening techniques for plants’ bioactive constituents have enabled phytochemical discovery for the prevention and treatment of challenging diseases such as cancer. Phytochemicals such as vincristine, vinblastine, paclitaxel, curcumin, colchicine, and lycopene have shown promising anticancer effects. Discovery of more plant-derived bioactive compounds should be encouraged via the exploitation of advanced and innovative research techniques, to prevent and treat advanced-stage cancers without causing significant adverse effects. This review highlights numerous plant-derived bioactive molecules that have shown potential as anticancer agents and their probable mechanisms of action and provides an overview of in vitro, in vivo and clinical trial studies on anticancer phytochemicals.

Arsenic sulfide inhibits the progression of gastric cancer through regulating the circRNA_ASAP2/Wnt/β-catenin pathway

In our paper, the effects of As4S4 treatments on the growth and migration of gastric cancer (GC) cells were explored, and the potential underlying molecular mechanisms were also identified. Cell viability was evaluated by cell counting kit 8 assay. The expression of Ki-67 was examined using immunofluorescence staining. Cell apoptosis was assessed by flow cytometry. The migratory and invasion abilities of cells were determined using Transwell assay. The mRNA and protein levels of related gene were examined by RT-qPCR and western blotting, respectively. CircRNAs chip was performed to identify the differentiated expression of circRNAs in GC cells following the treatment with As4S4. Our results revealed that the proliferation, migration and invasion of GC cells were remarkably suppressed by the treatment with As4S4, while cell apoptosis was promoted. Furthermore, circRNA_ASAP2 was a novel target of As4S4 in GC, and it is involved in As4S4-modulated biological behavior alterations in GC cells. In addition, the activities of the Wnt/β-catenin signaling in GC cells were affected by the overexpression circRNA_ASAP2 and the treatment with As4S4. Moreover, the behavior changes in GC cells caused by the knockdown of circRNA_ASAP2 were reversed by the treatment with Wnt agonist SKL2001. In summary, As4S4 could function as an antitumor agent in GC through regulating the circRNA_ASAP2/Wnt/β-catenin pathway, which in turn influences the growth and metastasis of GC cells.

Regulatory roles of phytochemicals on circular RNAs in cancer and other chronic diseases

As novel non-coding RNAs (ncRNAs), circular RNAs (circRNAs) play an essential role in the pathogenesis of many chronic diseases, and the regulation of these functional molecules has become a research hotspot gradually. Within the past decade, phytochemicals were reported to regulate the expression of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in various chronic diseases, and more recently, most studies focus on the regulatory roles of phytochemicals on circRNAs. Abnormal expression of circRNAs has been identified in chronic diseases like cancer, heart failure, depression and atherosclerosis, and numerous studies have revealed the modulation of circRNAs by phytochemicals including berberine, celastrol, cinnamaldehyde, curcumin, et al. The expression of circRNAs, such as circSATB2 and circFOXM1, were modulated by phytochemicals, and these regulations further affected cell proliferation, apoptosis, migration, invasion, autophagy, chemosensitivity, radiosensitivity and other biological processes. Mechanismly, the circRNAs mainly functioned as miRNA sponge, subsequently affecting miRNA-mediated regulation of target genes and related cell signaling pathways. In this review, we summarized the impact of phytochemicals on circRNAs expression and biological function, and discussed the mechanisms underlying phytochemicals regulating circRNAs in cancer and other chronic diseases.

Circular RNA circ_ASAP2 regulates drug sensitivity and functional behaviors of cisplatin-resistant gastric cancer cells by the miR-330-3p/NT5E axis

This study aims to explore the biological actions of circular RNA (circRNA) ArfGAP with SH3 domain, ankyrin repeat and PH domain 2 (circ_ASAP2, circ_0006089) in cisplatin (DDP) resistance of gastric cancer. Circ_ASAP2, ecto-5'-nucleotidase (NT5E) and miR-330-3p were quantified by quantitative real-time PCR or western blot. The measurements of the IC50 value and cell proliferation were done using 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell colony formation, cell cycle distribution, apoptosis, migration and invasion were evaluated by the colony formation, flow cytometry and transwell assays. Dual-luciferase reporter assay was performed to confirm the targeted relationship between different molecules. The role of circ_ASAP2 in tumor growth was gauged by in vivo animal studies. Circ_ASAP2 and NT5E were overexpressed in DDP-resistant gastric cancer tissues and cells. Knockdown of circ_ASAP2 promoted DDP sensitivity, apoptosis and repressed proliferation, migration and invasion of DDP-resistant gastric cancer cells in vitro and diminished tumor growth in vivo. Moreover, NT5E was a downstream effector of circ_ASAP2 in regulating cell DDP sensitivity and functional behaviors. Mechanistically, circ_ASAP2 directly bound to miR-330-3p to promote NT5E expression. Furthermore, circ_ASAP2 modulated cell DDP sensitivity and functional behaviors by targeting miR-330-3p. Knockdown of circ_ASAP2 promoted DDP sensitivity and suppressed malignant behaviors of DDP-resistant gastric cancer cells through targeting the miR-330-3p/NT5E axis.