Effects of Icaritin on the physiological activities of esophageal cancer stem cells

Prenylated chromones and flavonoids isolated from the roots of Flemingia macrophylla and their anti-lung cancer activity

BACKGROUND

The successful launch of icaritin, a therapeutic drug for liver cancer derived from Epimedium brevicornu, has provided new impetus for the development of prenylated flavonoids in the field of oncology. Flemingia macrophylla is reported to contain characteristic prenylated flavonoids which can regulate the p53 protein. We aimed to isolate these constituents and conduct activity evaluation, structure-activity relationship, and mechanism studies to provide candidate compounds for antitumor drug development.

METHODS

In this study, chromatographic techniques combined with spectroscopic methods were used to separate, purify, and identify the constituents of Flemingia macrophylla methanol extract. The cytotoxic activity of the constituents was evaluated using an MTT assay with A549 and H1975 cells as the model. The binding mechanism between the compounds and the p53 protein was investigated with molecular docking and validated with cellular thermal shift assay (CETSA). Western blotting (WB) was employed to detect the expression of p53 protein and apoptosis-related proteins in cells.

RESULTS

Chiral HPLC separation of racemates 1 and 7 provided two pairs of undescribed enantiomers (1a/1b and 7a/7b), along with eight known compounds (2 - 9) isolated from Flemingia macrophylla roots. Their structures were elucidated by spectroscopic analysis, and the absolute configurations of the enantiomers were determined from experimental and calculated electronic circular dichroism data. Compounds 1 - 7, and the non-prenyl analogues 10 - 13, were evaluated for cytotoxic activity against the human lung cancer A549 and H1975 cell line. Compounds 5 - 7 displayed better cytotoxicity than the positive control icaritin in A549 and H1975, with IC50 values ranging from 4.50 to 19.83 μmol·L-1 and < 5 μmol·L-1, respectively. The structure-activity relationships of the chromone or flavonoid analogues against A549 cells were discussed. Molecular docking results demonstrated that compound 7a has strong interaction with p53 and WB indicated that 7a induced apoptosis by increasing the p53 protein, decreasing the anti-apoptotic protein Bcl-2, and activating the caspase family in A549 cells. These results suggest that prenylated flavonoids are potential p53 protein activators.

CONCLUSION

This study demonstrates that Flemingia macrophylla is rich in prenylated flavonoid constituents, among which compounds 5 and 7 exhibited significant cytotoxic activity against A549 cells and served as reference candidates for the design and development of prenylated compounds as antitumor therapeutic drugs.

Icaritin: A phytomolecule with enormous pharmacological values

Pharmacological studies on flavonoids have always drawn much interest for many years. Icaritin (ICT), a representative flavone containing an 8-prenyl group, is a principal compound detected in medicinal plants of the genus Epimedum, the family Berberidaceae. Experimental results in the phytochemistry and pharmacology of this molecule are abundant now, but a deep overview has not been carried out. The goal of this review is to provide an insight into the natural observation, biosynthesis, biotransformation, synthesis, pharmacology, and pharmacokinetics of prenyl flavone ICT. The relevant data on ICT was collected from bibliographic sources, like Google Scholar, Web of Science, Sci-Finder, and various published journals. "Icaritin" alone or in combination is the main keyword to seek for references, and references have been updated till now. ICT is among the characteristic phytomolecules of Epimedum plants. Bacteria monitored its biosynthesis and biotransformation, while this agent was rapidly synthesized from phloroglucinol by microwave-assistance Claisen rearrangement. ICT is a potential agent in numerous in vitro and in vivo pharmacological records, which demonstrated its role in cancer treatments via apoptotic-related mechanisms. It also brings in various health benefits since it reduced harmful effects on the liver, lung, heart, bone, blood, and skin, and improved immune responses. Pharmacokinetic outcomes indicated that its metabolic pathway involved hydration, hydroxylation, dehydrogenation, glycosylation, and glucuronidation. Molecule mechanisms of action at a cellular level are predominant, but clinical studies are expected to get more. Structure-activity relationship records seem insufficient, and the studies on nano-combined approaches to improve its soluble property in living bodied medium are needed.

Epigenetic modifications in esophageal cancer: An evolving biomarker

Esophageal cancer is a widespread cancer of the digestive system that has two main subtypes: esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EA). In the diverse range of cancer therapy schemes, the side effects of conventional treatments remain an urgent challenge to be addressed. Therefore, the pursuit of novel drugs with multiple targets, good efficacy, low side effects, and low cost has become a hot research topic in anticancer therapy. Based on this, epigenetics offers an attractive target for the treatment of esophageal cancer, where major mechanisms such as DNA methylation, histone modifications, non-coding RNA regulation, chromatin remodelling and nucleosome localization offer new opportunities for the prevention and treatment of esophageal cancer. Recently, research on epigenetics has remained at a high level of enthusiasm, focusing mainly on translating the basic research into the clinical setting and transforming epigenetic alterations into targets for cancer screening and detection in the clinic. With the increasing emergence of tumour epigenetic markers and antitumor epigenetic drugs, there are also more possibilities for anti-esophageal cancer treatment. This paper focuses on esophageal cancer and epigenetic modifications, with the aim of unravelling the close link between them to facilitate precise and personalized treatment of esophageal cancer.

Icariin as an emerging candidate drug for anticancer treatment: Current status and perspective

Icariin (ICA) is a kind of natural flavonoid compound monomer, which is derived from the extract of dried stems and leaves of Epimedium. Modern pharmacological studies have found that ICA has broad bioactive function in affecting the biological processes of a variety of cancers, including breast cancer, colorectal cancer, hepatocellular carcinoma, esophageal cancer and other cancers, which indicates that ICA has promising application value in the treatment of cancer patients in the future. Nevertheless, the targets and molecular mechanisms of ICA in cancer treatment have not been elucidated in detail. Therefore, in this review, we systematically summarizes the current research progress of ICA in a series of cancers. In particular, an emphasis is placed on the mechanism of ICA and its future development direction, aiming at providing relevant theoretical basis for the development and application of ICA in the future cancer treatment strategies.

Icaritin-elevated circ_0000190 suppresses the malignant progression of multiple myeloma by targeting miR-301a

Icaritin has potential anticancer effects on various cancers, including multiple myeloma (MM). Recent studies claim that Icaritin can regulate the expression of noncoding RNAs (ncRNAs) in cancer development. This study aimed to investigate the role of circular RNA_0000190 (circ_0000190) and functional mechanism in Icaritin-treated MM. The expression of circ_0000190 and miR-301a was detected by quantitative real-time polymerase chain reaction. Cell cycle, apoptosis, migration, and invasion were investigated using flow cytometry assay, and transwell assay, respectively. The expression of BAX, BCL2, MMP2, and CCND1 was detected by western blot. The predicted target relationship between circ_0000190 and miR-301a was validated by dual-luciferase reporter assay and RNA immunoprecipitation assay. The activation of JAK1/STAT3 pathway was examined using western blot. Circ_0000190 was strikingly downregulated in MM specimens and cell lines, and Icaritin promoted the expression of circ_0000190. In function, circ_0000190 overexpression promoted MM cell cycle arrest and apoptosis but restrained the ability of migration and invasion. Icaritin blocked the development of MM by increasing circ_0000190 expression. MiR-301a was identified as a target of circ_0000190, and miR-301a reintroduction largely abolished the effects of circ_0000190 overexpression. The activation of JAK1/STAT3 pathway was promoted by miR-301a restoration. Icaritin played anticancer effects in MM partly by enhancing the expression of circ_0000190 and regulating the circ_0000190/miR-301a pathway. This study enhanced the understanding of the mechanism of Icaritin associated with circRNAs in MM.

Icaritin Inhibits Migration and Invasion of Human Ovarian Cancer Cells via the Akt/mTOR Signaling Pathway

Ovarian cancer (OC) is the most lethal of all gynecologic malignancies with poor survival rates. Although surgical treatment and chemotherapy had advanced to improve survival, platinum-based chemoresistance remains a major hurdle in the clinical treatment of OC. The search for novel active ingredients for the treatment of drug-resistant OC is urgently needed. Here, we demonstrated that icaritin, the main active ingredient derived from the traditional Chinese herb Epimedium genus, significantly suppressed the proliferation, migration, and invasion of both drug-susceptible and cisplatin-resistant OC cells in vitro. Mechanistically, icaritin at 20 μM significantly inhibited the phosphorylation of Akt and mTOR, as well as decreased the expression of vimentin and increased the expression of E-cadherin. Our data indicate that icaritin, a prenylated flavonoid natural product, could serve as a potential inhibitor of cisplatin-resistant OC by inhibiting the Akt/mTOR signaling pathway.

PPARγ mediates the anti-pulmonary fibrosis effect of icaritin

BACKGROUND

Pulmonary fibrosis is a fatal lung disease with limited treatment options. Icaritin is the active ingredient derived from the traditional Chinese medical plant Epimedium and possesses many biomedical activities. This study aimed to investigate the effects and molecular mechanisms of icaritin on bleomycin-induced pulmonary fibrosis in mice.

METHODS

To assess its preventative effects, bleomycin treated mice received 0, 0.04, 0.2, and 1 mg/kg of icaritin from day 1 onwards. To assess its therapeutic effects, bleomycin treated mice received 0 and 1 mg/kg of icaritin from day 15 onwards. Mice were sacrificed on day 21 and lung tissues were collected, stained with HE, Masson and immunohistochemistry. Q-PCR was used to measure Collagen I and Collagen III expression, western blotting was used to quantify α-SMA, Collagen I expression. Hydroxyproline content was measured using a biochemical method. NIH3T3 and HLF-1 cells were treated with TGF-β1with or without icaritin, and α-SMA, Collagen I were tested. PPARγ antagonist GW9662 and PPARγ-targeted siRNA were used to investigate the mechanism of icaritin in inhibiting myofibroblast differentiation.

RESULTS

Both preventative and therapeutic administration of icaritin improved the histopathological changes, decreased Collagen and α-SMA, lowered hydroxyproline content in bleomycin-treated lung tissues. Icaritin decreased α-SMA and Collagen I expression in TGF-β1-stimulated NIH3T3 and HLF-1 cells. However, its effect in reducing α-SMA and Collagen I expression was suppressed when expression or activity of PPARγ was inhibited.

CONCLUSIONS

Icaritin has therapeutic potential against pulmonary fibrosis via the inhibition of myofibroblast differentiation, which may be mediated by PPARγ.

A comparative study on the in vitro and in vivo antitumor efficacy of icaritin and hydrous icaritin nanorods

Icaritin (ICT) and hydrous icaritin (HICT) are two similar flavonoids compounds isolated from Epimedium Genus. This is the first comparative study on their in vitro and in vivo antitumor effects. Nanorods (NRs) were prepared for ICT and HICT by anti-solvent precipitation method using D-alpha tocopherol acid polyethylene glycol succinate (TPGS) as a stabilizer. The prepared ICT-NRs and HICT-NRs had similar diameter (155.5 nm and 201.7 nm), high drug loading content (43.30 ± 0.22% and 41.08 ± 0.19%), excellent stability and a similar sustaining drug release manner. Nanorods improved the in vitro toxicity against 4 different cancer cells in contrast to free ICT or free HICT; however, no significant difference was observed in this regard between ICT-NRs and HICT NRs. In the in vivo study on the anticancer efficacy on MCF-7 and PLC/PRE/5 tumor-bearing mice model, HICR-NRs displayed certain advantage over ICT NRs with higher tumor inhibition rate.

Therapeutic Strategies Against Cancer Stem Cells in Esophageal Carcinomas

Cancer stem cells (CSCs) in esophageal cancer have a key role in tumor initiation, progression and therapy resistance. Novel therapeutic strategies to target CSCs are being tested, however, more in-depth research is necessary. Eradication of CSCs can result in successful therapeutic approaches against esophageal cancer. Recent evidence suggests that targeting signaling pathways, miRNA expression profiles and other properties of CSCs are important strategies for cancer therapy. Wnt/β-catenin, Notch, Hedgehog, Hippo and other pathways play crucial roles in proliferation, differentiation, and self-renewal of stem cells as well as of CSCs. All of these pathways have been implicated in the regulation of esophageal CSCs and are potential therapeutic targets. Interference with these pathways or their components using small molecules could have therapeutic benefits. Similarly, miRNAs are able to regulate gene expression in esophageal CSCs, so targeting self-renewal pathways with miRNA could be utilized to as a potential therapeutic option. Moreover, hypoxia plays critical roles in esophageal cancer metabolism, stem cell proliferation, maintaining aggressiveness and in regulating the metastatic potential of cancer cells, therefore, targeting hypoxia factors could also provide effective therapeutic modalities against esophageal CSCs. To conclude, additional study of CSCs in esophageal carcinoma could open promising therapeutic options in esophageal carcinomas by targeting hyper-activated signaling pathways, manipulating miRNA expression and hypoxia mechanisms in esophageal CSCs.

Molecular and cellular basis of the anticancer activity of the prenylated flavonoid icaritin in hepatocellular carcinoma

The prenylated flavonoid icaritin (ICT) is currently undergoing phase 3 clinical trial for the treatment of advanced hepatocellular carcinoma (HCC), based on a solid array of preclinical and clinical data. The antitumor activity originates from the capacity of the drug to modulate several signaling effectors in cancer cells, mainly the estrogen receptor splice variant ERα36, the transcription factors STAT3 and NFκB, and the chemokine receptor CXCR4. Recent studies have implicated additional components, including different microRNAs, the generation of reactive oxygen species and the targeting of sphingosine kinase-1. ICT also engages the RAGE-HMGB1 signaling route and modulates the apoptosis/autophagy crosstalk to promote its anticancer activity. In addition, ICT exerts profound changes on the tumor microenvironment to favor an immune-response. Collectively, these multiple biochemical and cellular characteristics confer to ICT a robust activity profile which can be exploited to treat HCC, as well as other cancers, including glioblastoma and onco-hematological diseases such as chronic myeloid leukemia. This review provides an update of the pharmacological properties of ICT and its metabolic characteristics. It also addresses the design of derivatives, including both natural products and synthetic molecules, such as SNG1153 also in clinical trial. The prenylated flavonoid ICT deserves attention as a multifunctional natural product potentially useful to improve the treatment of advanced hepatocellular carcinoma.

Icaritin: A Novel Natural Candidate for Hematological Malignancies Therapy

Hematological malignancies including leukemia and lymphoma can severely impact human health. With the current therapies combined with chemotherapy, stem cell transplantation, radiotherapy, and immunotherapy, the prognosis of hematologic malignancies improved significantly. However, most hematological malignancies are still incurable. Therefore, research for novel treatment options was continuing with the natural product as one source. Icaritin is a compound extracted from a traditional Chinese herb, Epimedium Genus, and demonstrated an antitumor effect in various neoplasms including hematological malignancies such as leukemia, lymphoma, and multiple myeloma. In hematological malignancies, icaritin showed multiple cytotoxic effects to induce apoptosis, arrest the cell cycle, inhibit proliferation, promote differentiation, restrict metastasis and infiltration, and suppress the oncogenic virus. The proved underlying mechanisms of the cytotoxic effects of icaritin are different in various cell types of hematological malignancies but associated with the critical cell signal pathway, including PI3K/Akt, JAK/STAT3, and MAPK/ERK/JNK. Although the primary target of icaritin is still unspecified, the existing evidence indicates that icaritin is a potential novel therapeutic agent for neoplasms as with hematological malignancies. Here, in the field of hematology, we reviewed the reported activity of icaritin in hematologic malignancies and the underlying mechanisms and recognized icaritin as a candidate for therapy of hematological malignancies.