Apigenin suppresses migration and invasion of transformed cells through down-regulation of C-X-C chemokine receptor 4 expression

Effect of Thymbra capitata (L.) Cav. on Inflammation, Senescence and Cell Migration

Aromatic plants are reported to display pharmacological properties, including anti-aging. This work aims to disclose the anti-aging effect of the essential oil (EO) of Thymbra capitata (L.) Cav., an aromatic and medicinal plant widely used as a spice, as well as of the hydrodistillation residual water (HRW), a discarded by-product of EO hydrodistillation. The phytochemical characterization of EO and HRW was assessed by GC-MS and HPLC-PDA-ESI-MSⁿ, respectively. The DPPH, ABTS, and FRAP assays were used to disclose the antioxidant properties. The anti-inflammatory potential was evaluated using lipopolysaccharide-stimulated macrophages by assessing NO production, iNOS, and pro-IL-1β protein levels. Cell migration was evaluated using the scratch wound assay, and the etoposide-induced senescence was used to assess the modulation of senescence. The EO is mainly characterized by carvacrol, while the HRW is predominantly characterized by rosmarinic acid. The HRW exerts a stronger antioxidant effect in the DPPH and FRAP assays, whereas the EO was the most active sample in the ABTS assay. Both extracts reduce NO, iNOS, and pro-IL-1β. The EO has no effect on cell migration and presents anti-senescence effects. In opposition, HRW reduces cell migration and induces cellular senescence. Overall, our study highlights interesting pharmacological properties for both extracts, EO being of interest as an anti-aging ingredient and HRW relevant in cancer therapy.

Apigenin in cancer prevention and therapy: A systematic review and meta-analysis of animal models

BACKGROUND

Apigenin is being increasingly recognized as a cancer chemopreventive agent. We aimed to investigate the anticancer effects of Apigenin in in-vivo studies to know its present research status and how close or how far it is from the clinics.

METHODS

Several electronic databases such as PubMed, Springer, Cochrane, and ctri.gov.in were searched to fetch the relevant articles. We focused only on published animal studies that reported the anticancer effects of Apigenin against various cancers. Two reviewers independently assessed the risk of bias for each analysis, and the conflicting views were resolved later by consensus.

RESULTS

A total of 25 studies focused on the anticancer effects of Apigenin on various cancer types, including liver, prostate, pancreatic, lung, nasopharyngeal, skin, colon, colorectal, colitis-associated carcinoma, head and neck squamous cell carcinoma, leukemia, renal cell carcinoma, Ehrlich ascites carcinoma, and breast cancer were included. Overall, Apigenin reduces tumor volume (SMD=-3.597, 95% CI: -4.502 to -2.691, p < 0.001), tumor-weight (SMD=-2.213, 95% CI: -2.897 to -1.529, p < 0.001), tumor number (SMD=-1.081, 95% CI: -1.599 to -0.563, p < 0.001) and tumor load (SMD=-1.556, 95% CI: -2.336 to -0.776, p < 0.001). Further, it has no significant effect on the animal's body-weight (SMD=-0.345, 95% CI: -0.832 to 0.143, p = 0.165). Apigenin exerts anti-tumor effects mainly by inducing apoptosis/cell-cycle arrest.

CONCLUSIONS

Our analysis suggests that Apigenin has potential anticancer effects against various cancers. However, the poor symmetry of the funnel plot suggested publication bias. Thus, it warrants further research to evaluate the potential of Apigenin alone or as an adjuvant for cancer treatment.

Rationalizing the therapeutic potential of apigenin against cancer

BACKGROUND

Despite the remarkable advances made in the diagnosis and treatment of cancer during the past couple of decades, it remains the second largest cause of mortality in the world, killing approximately 9.6 million people annually. The major challenges in the treatment of the advanced stage of this disease are the development of chemoresistance, severe adverse effects of the drugs, and high treatment cost. Therefore, the development of drugs that are safe, efficacious, and cost-effective remains a 'Holy Grail' in cancer research. However, the research over the past four decades shed light on the cancer-preventive and therapeutic potential of natural products and their underlying mechanism of action. Apigenin is one such compound, which is known to be safe and has significant potential in the prevention and therapy of this disease.

AIM

To assess the literature available on the potential of apigenin and its analogs in modulating the key molecular targets leading to the prevention and treatment of different types of cancer.

METHOD

A comprehensive literature search has been carried out on PubMed for obtaining information related to the sources and analogs, chemistry and biosynthesis, physicochemical properties, biological activities, bioavailability and toxicity of apigenin.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and a few cohort studies that evidenced the effectiveness of apigenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK/ERK, Wnt/β-catenin, etc., which play a crucial role in the development and progression of cancer. In addition, apigenin was also shown to inhibit chemoresistance and radioresistance and make cancer cells sensitive to these agents. Reports have further revealed the safety of the compound and the adaptation of nanotechnological approaches for improving its bioavailability.

SIGNIFICANCE

Hence, the present review recapitulates the properties of apigenin and its pharmacological activities against different types of cancer, which warrant further investigation in clinical settings.

Apigenin as an effective anticancer natural product: Spotlight on TRAIL, WNT/β-catenin, JAK-STAT pathways, and microRNAs

Wealth of information gleaned from decades of high-impact research work; scientists have disentangled the complicated web of versatile regulators that underlie cancer development and progression. Use of structural biology approaches and functional genomics have helped us to gain new insights into complex nature of cancer, and it is now clear that genetic/epigenetic mutations, overexpression of oncogenes, inactivation of tumor suppressors, loss of apoptosis, and versatility of protein binding partners have contributory roles in carcinogenesis and metastatic spread. It is becoming progressively more understandable that reprogramming of gene expression during and nontranscriptional changes during cancer development and progression are initiated and controlled by deregulated signal transduction cascades, all of which collectively create an incalculable complexity. Data obtained through preclinical and clinical trials revealed that alterations in the targeted oncogenes and other downstream, and parallel pathways played a central role in the development of resistance against different therapeutics. Phytochemicals have regained limelight, and different natural products are currently being tested for efficacy in preclinical studies. Apigenin, a plant-derived flavonoid has considerable pharmacological value and is reportedly involved in the regulation of different signaling cascades. In this review, we have attempted to summarize rapidly evolving understanding of molecular biologists and pharmacologists about the potential of apigenin in the regulation of deregulated signaling pathways in different cancers. We have emphasized on the regulation of WNT/β-catenin and janus kinase/signal transducers and activators of transcription (JAK-STAT) pathways. We also comprehensively discuss how apigenin restored apoptosis in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistant cancers. The review also gives a snapshot of microRNAs (miRNAs) that regulate wide-ranging biological processes, and it is now clear that each miRNA can control hundreds of gene targets. Apigenin was noted to upregulate miR-520b and miR-101 in different cancers to inhibit tumor growth. Moreover, apigenin-induced apoptotic rate was significantly higher when used in combination with miR-423-5p inhibitors or miR-138 mimics. Better comprehension of linear and integrated signaling pathways will be helpful in effective therapeutic targeting of deregulated signaling pathways to inhibit/prevent cancer.

Phytochemical Study and Evaluation of the Cytotoxic Properties of Methanolic Extract from Baccharis obtusifolia

Some species of the Baccharis genus have been shown to possess important biomedical properties, including cytotoxic activity. In this study, we examined the cytotoxic effect of methanol extract from Baccharis obtusifolia (Asteraceae) in cancer cell lines of prostate (PC-3), colon (RKO), astrocytoma (D-384), and breast (MCF-7). The methanolic extract displayed the largest substantial cytotoxic effect in lines of colon cancer (RKO) and cerebral astrocytoma (D-384). Chromatographic purification of the B. obtusifolia methanolic extract led to the isolation and identification of 5,4′-dihydroxy-7-methoxyflavone (1) and 5-hydroxy-7,4′-dimethoxyflavone (2) compounds of the flavonoid type.

Stachydrine suppresses viability & migration of astrocytoma cells via CXCR4/ERK & CXCR4/Akt pathway activity

AIM

Pilocytic astrocytomas (PAs) are a common adolescent malignancy. We evaluated the effects of the betaine stachydrine on human PA cells as well as its associated molecular mechanism(s).

MATERIALS & METHODS

Various experiments assessing stachydrine's effects on the human PA cell line Res186 were performed.

RESULTS & CONCLUSION

Stachydrine dose-dependently suppressed proliferation and colony formation in Res186 cells with no such effect on normal astrocytes. Stachydrine downregulated CXCR4 transcription through enhancing IκBα-based NF-κB inhibition. Stachydrine promoted apoptosis and cyclin D1/p27^Kip1-associated G0/G1 phase arrest in a CXCR4/ERK- and CXCR4/Akt-dependent manner. Stachydrine suppressed MMP-associated migration and invasiveness via inhibiting CXCR4/Akt/MMP-9/2 and CXCR4/ERK/MMP-9/2 pathway activity. Stachydrine inhibits the viability, migration and invasiveness of human PA cells via inhibiting CXCR4/ERK and CXCR4/Akt signaling.

Effects of Apigenin and Apigenin- Loaded Nanogel on Induction of Apoptosis in Human Chronic Myeloid Leukemia Cells

Background:

Diet plays an important role in cancer prevention. Apigenin, a flavonoid with thechemical formula C15H10O5 , is abundantly present in vegetables. Vegetarian foods containing flavonoids are rich sources of bioactive compounds. Flavonoids have been utilized in herbal treatment. Nanogels are drug delivery systems based on polymers and are used in tissue engineering and for drug delivery. This study was conducted to compare the effects of apigenin and a nanodrug on the viability of the K562 cell line of chronic myeloid leukemia at different durations under laboratory conditions.

Materials and Methods:

Chitosan was first dissolved in 1% acetic acid, and ethylene dichloride EDC and NHS were added to the solution. Then, the nanodrug was prepared by loading apigenin into stearate–chitosan nanogel (scs nanogel), and its physical and morphological characteristics were evaluated by TEM, DLS, and FTIR. Trypan blue staining, MTT assay, and flow cytometry were used to analyze the effects of various concentrations of apigenin and apigenin-loaded chitosan–stearate nanogel (APG–SCS) at 24, 48, and 72 h after they were applied to the K562 cell line.

Results:

The diameter of the nanodrug particles was measured using DLS and confirmed by TEM. The K562 cells treated with APG–SCS and with apigenin exhibited significant differences compared with the control (P < 0.05). Apoptosis was detected by flow cytometry.

Conclusion:

This study showed that the toxic effects of apigenin and the nanodrug improved with increasing concentrations and exposure durations compared to those in the control.The toxic effect of apigenin loaded into the stearate-chitosan nanogel was greater than apigenin, and the toxic effects of both materials were greater compared to the control under laboratory conditions.

The flavonoid apigenin reduces prostate cancer CD44(+) stem cell survival and migration through PI3K/Akt/NF-κB signaling

AIMS

Cancer stem cells (CSCs) are involved in drug resistance, metastasis and recurrence of cancers. The efficacy of apigenin on cell survival, apoptosis, migration and stemness properties were analyzed in CSCs.

MAIN METHODS

Prostate CSCs (CD44(+)) were isolated from human prostate cancer (PCa) PC3 cells using a magnetic-activated cell sorting system. PC3 and CSCs were treated with various concentrations of apigenin, docetaxel and their combinations for 48h.

KEY FINDINGS

Apigenin dose dependently inhibited CSCs and PC3 cell survival, and this was accompanied with a significant increase of p21 and p27. Apigenin induced apoptosis via an extrinsic caspase-dependent pathway by upregulating the mRNA expressions of caspases-8, -3 and TNF-α, but failed to regulate the intrinsic pathway as determined by the Bax, cytochrome c (Cyt-c) and APAF-1 in CSCs. In contrary to CSCs, apigenin induced intrinsic apoptosis pathway as evidenced by the induction of Bax, Cyt-c and caspase-3 while caspase-8, TNF-α and Bcl-2 levels remained unchanged in PC3 cells. The flavonoid strongly suppressed the migration rate of CSCs compared to untreated cells. Significant downregulation of matrix metallopeptidases-2, -9, Snail and Slug exhibits the ability of apigenin treatment to suppress invasion. The expressions of NF-κB p105/p50, PI3K, Akt and the phosphorylation of pAkt were decreased after apigenin treatment. Moreover, apigenin treatment significantly reduced pluripotency marker Oct3/4 protein expression which might be associated with the down-regulation of PI3K/Akt/NF-κB signaling.

SIGNIFICANCE

Our data indicated that, apigenin could be a useful compound to prevent proliferation and migration of cancer cells as well as CSCs.

Apigenin, a potent suppressor of dendritic cell maturation and migration, protects against collagen-induced arthritis

This study aimed to investigate whether apigenin (API) suppresses arthritis development through the modulation of dendritic cell functions. Bone marrow-derived dendritic cells (BMDCs) were stimulated in vitro with lipopolysaccharide (LPS) and treated with API for 24 hrs; DC functions, including phenotype expressions, cytokine secretion, phagocytosis and chemotaxis, were then investigated. The effects of API on collagen-induced arthritis (CIA) were examined in vivo, and purified DCs from the lymph nodes (LNs) of API-treated CIA mice were analysed for phenotypes and subsets. In in vitro, API efficiently restrained the phenotypic and functional maturation of LPS-stimulated BMDCs while maintaining phagocytotic capabilities. Moreover, API inhibited the chemotactic responses of LPS-stimulated BMDCs, which may be related to the depressive effect on chemokine receptor 4 (CXCR4). In in vivo, API treatment delayed the onset and reduced the severity of arthritis in CIA mice, and diminished secretion of pro-inflammatory cytokines in the serum and supernatants from the LN cells of the CIA mice. Similar to the in vitro findings, the API-treated mice exhibited reduced expression of co-stimulatory molecules and major histocompatibility complex II on DCs. Furthermore, API treatment strongly down-regulated the number of Langerhans cells, but not plasmacytoid DCs (pDCs) in LNs, which may be related to the depressive effect of API on the expression of CXCR4 on DCs of peripheral blood. These data provide new insight into the mechanism of action of API on arthritis and indicate that the inhibition of maturation and migration of DCs by API may contribute to its immunosuppressive effects.

Ethnopharmacological Significance of Eclipta alba (L.) Hassk. (Asteraceae)

Eclipta alba can be found growing wild in fallow lands of Bangladesh where it is considered as a weed by farmers. Traditional medicinal systems of the Indian subcontinent countries as well as tribal practitioners consider the plant to have diverse medicinal values and use it commonly for treatment of gastrointestinal disorders, respiratory tract disorders (including asthma), fever, hair loss and graying of hair, liver disorders (including jaundice), skin disorders, spleen enlargement, and cuts and wounds. The plant has several phytoconstituents like wedelolactone, eclalbasaponins, ursolic acid, oleanolic acid, luteolin, and apigenin. Pharmacological activities of plant extracts and individual phytoconstituents have revealed anticancer, hepatoprotective, snake venom neutralizing, anti-inflammatory, and antimicrobial properties. Phytoconstituents like wedelolactone and ursolic and oleanolic acids as well as luteolin and apigenin can form the basis of new drugs against cancer, arthritis, gastrointestinal disorders, skin diseases, and liver disorders.

Anti-invasive effects of celastrol in hypoxia-induced fibroblast-like synoviocyte through suppressing of HIF-1α/CXCR4 signaling pathway

Rheumatoid arthritis (RA) joints are in a hypoxic condition. Hypoxia-induced migration and invasion of fibroblast-like synoviocytes (FLSs) are considered to play a critical role in the pathogenesis of RA. Among the key genes upregulated by hypoxia-inducible factor-1α (HIF-1α), CXC chemokine receptor 4 (CXCR4) plays an important role in FLS migration and invasion. Our previous studies have shown that celastrol exerts anti-arthritic effects by inhibiting FLS migration and invasion under normoxic conditions. However, the effect and molecular mechanisms underlying the effect of celastrol on hypoxia-induced FLS migration and invasion are poorly understood. In the present study, we assessed the effect of celastrol on hypoxia-induced FLS migration and invasion. Results showed that celastrol suppressed hypoxia-induced FLS migration and invasion. In addition, we also found that celastrol inhibited hypoxia-induced CXCR4 expression at both the mRNA and the protein levels in RA-FLSs. Meanwhile, it is revealed that celastrol inhibited the transcriptional activity of CXCR4 under hypoxic conditions by suppressing the binding activity of HIF-1α in the CXCR4 promoter, and blocked hypoxia-induced accumulation of nuclear HIF-1α. Furthermore, treatment with HIF-1α inhibitor reduced the hypoxia-induced expression and transcriptional activity of CXCR4. In conclusion, our results indicate that celastrol inhibits hypoxia-induced migration and invasion via suppression of HIF-1α mediated CXCR4 expression in FLSs under hypoxic conditions. These results provide a strong rationale for further testing and validation of the use of celastrol as a new alternative for using in the treatment of RA.