Geraniin suppresses tumor cell growth and triggers apoptosis in human glioma via inhibition of STAT3 signaling

Geraniin: A dietary ellagitannin as a modulator of signalling pathways in cancer progression

Cancer remains a global health challenge, necessitating the exploration of novel therapeutic agents. Current treatment options are unable to overwhelm and cure the cancer burden. Hence, identifying new bioactive molecular entities with potent anticancer activity is the need of the hour. Ellagitannin Geraniin (GN) is one such evidence-based novel bioactive molecular entity (BME) available from different natural sources that can effectively combat cancer. This narrative review attempts to investigate the potential of BME-GN from 2005 to 2023 as an efficient molecular anti-cancer therapeutic against diverse cancers. We provide information on GN's pharmacological advantages, metabolite profile, and capacity to modulate multiple molecular targets involved in the hallmarks of cancer. Using the search terms "Geraniin," "Gallic acid," "Ellagitannin," "pharmacological properties," "health," "antioxidant," "apoptosis," "disease management," "anti-proliferative," "in vitro," "anti-inflammatory," "anti-angiogenic," "in vivo," and "clinical trials," We searched the scientific literature using Scopus, Web of Science, Google Scholar, and PubMed. We removed publications that included overlap or equivalent content and used the most recent review on each issue as our primary reference. From an initial pool of 430 articles, 52 studies met the search criteria. These studies collectively provide substantial in vitro, in vivo, and clinical evidence of GN's potential to combat diverse cancers. Mechanistic insights revealed its involvement in fostering apoptosis, anti-inflammatory, and modulation of key signalling pathways implicated in the hallmarks of cancer. GN's pleiotropic pharmacological and molecular therapeutic properties strongly suggest its potential as a promising anticancer agent.

Biopolymeric nanoparticles based effective delivery of bioactive compounds toward the sustainable development of anticancerous therapeutics

Nowadays, effective cancer therapy is a global concern, and recent advances in nanomedicine are crucial. Cancer is one of the major fatal diseases and a leading cause of death globally. Nanotechnology provides rapidly evolving delivery systems in science for treating diseases in a site-specific manner using natural bioactive compounds, which are gaining widespread attention. Nanotechnology combined with bioactives is a very appealing and relatively new area in cancer treatment. Natural bioactive compounds have the potential to be employed as a chemotherapeutic agent in the treatment of cancer, in addition to their nutritional benefits. Alginate, pullulan, cellulose, polylactic acid, chitosan, and other biopolymers have been effectively used in the delivery of therapeutics to a specific site. Because of their biodegradability, biopolymeric nanoparticles (BNPs) have received a lot of attention in the development of new anticancer drug delivery systems. Biopolymer-based nanoparticle systems can be made in a variety of ways. These systems have developed as a cost-effective and environmentally friendly solution to boost treatment efficacy. Effective drug delivery systems with improved availability, increased selectivity, and lower toxicity are needed. Recent research findings and current knowledge on the use of BNPs in the administration of bioactive chemicals in cancer therapy are summarized in this review.

Geraniin inhibits whole blood IFN-γ and IL-6 and promotes IL-1β and IL-8, and stimulates calcium-dependent and sucrose-sensitive erythrocyte death

Correlations between circulating cytokine levels and disease states are well established, and pharmacological modulation of the immune response is thus an important aspect of the assessment of investigational new drugs. Moreover, chemotherapy-related anemia is a major obstacle in cancer treatment. Geraniin (GRN), a tannin extracted from Geranium and other plants, possesses promising antitumor potential. However, the effect of GRN on whole blood (WB) cytokine response and RBC physiology remains unexplored. Heparinized blood from consented, healthy adults was challenged with 100 ng/mL of lipopolysaccharide (LPS) with and without pretreatment with 10 μM of GRN for 24 h at 37 °C, and tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, and IL-10 were assayed by ELISA. Moreover, single-cell RBC suspensions were treated with 5-100 μM of GRN for 24 or 48 h at 37 °C and cytotoxicity and canonical eryptotic markers were examined by flow cytometry. It was revealed that GRN significantly attenuated LPS-induced IFN-γ levels, increased IL-1β, decreased IL-6 only in absence of LPS, and aggravated LPS-induced IL-8 while together with LPS significantly diminished IL-10. Furthermore, GRN induced dose-responsive, Ca²⁺-dependent, and sucrose-sensitive hemolysis, along with phosphatidylserine exposure and Ca²⁺ accumulation with no appreciable cell shrinkage or oxidative damage. GRN was also selectively toxic to platelets, significantly delayed reticulocyte maturation, and significantly disrupted leukocyte proportions. In conclusion, GRN regulates the WB cytokine response and promotes premature hemolysis and eryptosis. This study provides insights into the therapeutic utility of GRN in a highly relevant cellular model system.

Tannins in Terminalia bellirica inhibit hepatocellular carcinoma growth by regulating EGFR-signaling and tumor immunity

The fruits of Terminalia bellirica (Gaertn.) Roxb. (TB) are used as a multi-use therapeutic herbal product in the Tibetan medicinal system and are prescribed as a general health tonic in the traditional Ayurvedic medicinal system. It has been demonstrated that these fruits have a variety of pharmacological activities, including anti-tumor, anti-oxidative, anti-inflammatory, hepatoprotective and immunoregulatory effects, etc. However, the therapeutic effects of tannins in TB on HCC and the underlying mechanisms remain uncharacterized. In the current study, we aimed to identify the anti-tumor effect of tannins in TB by employing a H22 xenograft mouse model and by performing cell-based in vitro studies with the assistance of the network pharmacology analysis. The crude extract of TB was purified to yield total tannin fraction (TB-TF), and our results found that TB-TF significantly inhibited the tumor growth of H22 xenografts in mice by inducing apoptosis and reducing angiogenesis. A total of 90 compounds were then identified in TB-TF by UPLC-MS/MS, and 27 were found in serum after oral administration of TB-TF in mice. The network pharmacology analysis based on these absorbed components was performed and, along with experimental evidence, it revealed that the ERBB, PI3K-Akt, and MAPK signaling pathways may be involved in the anti-tumor effect of TB-TF on HCC. Furthermore, we suggested that TB-TF effectively modulated the immunosuppressive tumor microenvironment in H22 xenograft mice. In summary, our study demonstrated that TB-TF could be developed as a functional food, which is not only a promising anti-cancer reagent but also a potential candidate with bright prospects for the emerging trends of immunotherapy for HCC.

Natural heat shock protein 90 inhibitors in cancer and inflammation

Heat shock protein (HSP)90 is the most abundant HSPs, which are chaperone molecules whose major roles are cell protection and maintenance by means of aiding the folding, the stabilization and the remodeling of a wide range of proteins. A few hundreds of proteins depend on HSP90 chaperone activity, including kinases and transcriptional factors that play essential roles in cancer and inflammation, so that HSP90-targeted therapies have been considered as a potential strategy for the treatment of cancer and inflammatory-associated diseases. HSP90 inhibition by natural, semi-synthetic and synthetic compounds have yield promising results in pre-clinical studies and clinical trials for different types of cancers and inflammation. Natural products are a huge source of biologically active compounds widely used in drug development due to the great diversity of their metabolites which are capable to modulate several protein functions. HSP90 inhibitors have been isolated from bacteria, fungi and vegetal species. These natural compounds have a noteworthy ability to modulate HSP90 activity as well as serve as scaffolds for the development of novel synthetic or semi-synthetic inhibitors. Over a hundred clinical trials have evaluated the effect of HSP90 inhibitors as adjuvant treatment against different types of tumors and, currently, new studies are being developed to gain sight on novel promising and more effective approaches for cancer treatment. In this review, we present the naturally occurring HSP90 inhibitors and analogues, discussing their anti-cancer and anti-inflammatory effects.

microRNA cluster MC-let-7a-1~let-7d promotes autophagy and apoptosis of glioma cells by down-regulating STAT3

Background

Accumulating evidence has highlighted the correlation between microRNAs (miRNAs) and the progression of glioma. However, the role of miR cluster MC‐let‐7a‐1 ~ let‐7d in glioma remains elusive. Thus, the current study aimed to investigate the effect of miR cluster MC‐let‐7a‐1 ~ let‐7d on glioma progression.

Methods and Results

Microarray data analysis provided data indicating the involvement of miR cluster MC‐let‐7a‐1 ~ let‐7d in glioma via STAT3. The expression of let‐7a‐1, let‐7d, let‐7f‐1, and miR cluster MC‐let‐7a‐1 ~ let‐7d was diminished in the glioma tissues and the cell lines. Additionally, our results revealed that STAT3 was a target gene of let‐7d, let‐7a‐1, and let‐7f‐1, which was further verified by the dual‐luciferase reporter gene assay. Moreover, STAT3 expression was negatively mediated by let‐7a‐1, let‐7d, and let‐7f‐1. Up‐regulated miR cluster MC‐let‐7a‐1 ~ let‐7d or silenced STAT3 suppressed cell proliferation but accelerated cell apoptosis and autophagy. Moreover, restrained tumor growth was identified in the nude mice treated with miR cluster MC‐let‐7a‐1 ~ let‐7d mimics or STAT3 siRNA.

Conclusion

Taken together, the miR cluster MC‐let‐7a‐1 ~ let‐7d promotes glioma cell autophagy and apoptosis by repressing STAT3. The current study highlights the potential of the miR cluster MC‐let‐7a‐1 ~ let‐7d as biomarkers and promising treatment strategies for glioma.

Bioactive Compounds: Natural Defense Against Cancer?

Cancer is a devastating disease that has claimed many lives. Natural bioactive agents from plants are gaining wide attention for their anticancer activities. Several studies have found that natural plant-based bioactive compounds can enhance the efficacy of chemotherapy, and in some cases ameliorate some of the side-effects of drugs used as chemotherapeutic agents. In this paper, we have reviewed the literature on the anticancer effects of four plant-based bioactive compounds namely, curcumin, myricetin, geraniin and tocotrienols (T3) to provide an overview on some of the key findings that are related to this effect. The molecular mechanisms through which the active compounds may exert their anticancer properties in cell and animal-based studies also discussed.

Prospect of natural products in glioma: A novel avenue in glioma management

Glioma is one of the most perplexing cancers because of its infiltrating nature, molecular signaling, and location in central nervous system. Blood-brain barrier acts as a natural barrier to the glioma making it difficult to access by conventional chemotherapy. Clinicians are using natural compounds or their derivatives for several diseases including different cancers. However, the feasibility of using natural compounds in glioma is not explored in details. Natural compounds can act over a wide variety of signaling pathways such as survival and metabolic pathways and induce cell death. Some of the natural agents have additional benefits of crossing biological barriers such as blood-brain barrier with ease having few or no impact on the surrounding healthy cells. All of these benefits make natural compounds a prospective candidate for the glioma management. This article evaluates the benefits of using natural compounds for glioma therapy and their possible mechanism of actions. We have discussed the natural compounds assessed currently for glioma therapy and proposed a few novel natural compounds with potential antiglioma effect based on their mechanism of action.

Geraniin Differentially Modulates Chromosome Stability of Colon Cancer and Noncancerous Cells by Oppositely Regulating their Spindle Assembly Checkpoint

Geraniin has been reported to specifically induce apoptosis in multiple human cancers, but the underlying mechanism is poorly defined. The spindle assembly checkpoint (SAC) is a surveillance system to ensure high-fidelity chromosome segregation during mitosis. Weakening of SAC to enhance chromosome instability (CIN) can be therapeutic because very high levels of CIN are lethal. In this study, we have investigated the effects of geraniin on the SAC of colorectal cancer HCT116 cells and noncancerous colon epithelial CCD841 cells. We find that treatment of HCT116 cells with geraniin leads to dose-dependent decrease of cell proliferation, colony formation, and anchorage-independent growth. Geraniin is found to induce apoptosis in mitotic and postmitotic HCT116 cells. Furthermore, geraniin weakens the SAC function of HCT116 cells by decreasing the transcriptional expression of several SAC kinases (particularly Mad2 and Bub1), which in turn leads to premature anaphase entry, mitotic aberrations, and CIN in HCT116 cells. In contrast, the proliferation of CCD841 cells is slightly inhibited by geraniin. Even more interestingly, geraniin increases the transcriptional expression of several SAC kinases (e.g., Mad1 and BubR1) to strengthen SAC efficiency, which contributes to the reduction of mitotic aberrations and CIN in CCD841 cells. Altogether, our findings reveal that the SAC pathway in human colon cancer and noncancerous cell lineages responses oppositely to geraniin treatment, resulting CIN promotion and suppression, respectively. Specific abrogation of SAC to induce catastrophic CIN in HCT116 cells may account for the selective anticancer action of geraniin.. Environ. Mol. Mutagen. 60:254-268, 2019. © 2018 Wiley Periodicals, Inc.

Effects of 17-allylamino-17-demethoxygeldanamycin on the induction of apoptosis and cell cycle arrest in HCT-116 cells

The present study investigated the effects of HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) on apoptosis and the cell cycle of the HCT-116 human colon carcinoma cell line, with the aim of elucidating their underlying mechanisms. MTT was used to examine the inhibitory effects of 17-AAG on the proliferation of HCT-116 cells at various time points and doses. The cells were stained with Annexin V-fluorescein isothiocyanate/propidium iodide and evaluated by flow cytometry. The expression of signal transducer and activator of transcription (STAT)3, cyclin D1, cytochrome c (cyt-c), caspase 9 and caspase 3 at the mRNA and protein level was determined using reverse transcription-polymerase chain reaction and western blotting. Treatment with 17-AAG at a concentration of 1.25-20 mg/l for 24 and 48 h significantly inhibited the proliferation of HCT-116 cells in a time-dependent and concentration-dependent manner. Treatment with 17-AAG at concentrations of 1.25, 2.5 and 5 mg/l for 48 h significantly induced apoptosis and cell cycle arrest in HCT-116 cells. Exposure to 17-AAG at concentrations of 1.25, 2.5 and 5 mg/l for 48 h significantly downregulated the mRNA and protein expression of STAT3 and cyclin D1, but upregulated cyt-c, caspase 9 and caspase 3 in a concentration-dependent manner in HCT-116 cells. Therefore 17-AAG is able to inhibit cell proliferation, inducing apoptosis and G₁ stage cell cycle arrest by downregulating the expression of cyclin D1, and promoting the mitochondria apoptosis by downregulating STAT3 in HCT-116 cells.