Astragaloside IV downregulates the expression of MDR1 in Bel-7402/FU human hepatic cancer cells by inhibiting the JNK/c-Jun/AP-1 signaling pathway

Herb-drug interaction potential of Astragali Radix: a metabolic perspective

Astragali Radix (AR) is one of the most widely used herbs in Asia and has a wide range of biological activities. These activities are attributed to its various compounds like flavonoids, saponins, and polysaccharides. AR and its major components are often used in combination with other drugs for the treatment of diseases such as cancer and cerebral ischemia. With the expanding range of AR combinations, the potential for herb-drug interaction (HDI) has been raised. Key targets in HDI studies include drug-metabolizing enzymes (DMEs) and transporters. Existing studies have shown that AR and its major components have various regulatory effects on these targets, notably CYP2C9, CYP3A4, UGT1A6, and P-gp. AR may contribute to HDI when it is taken with substrates of these biomolecules, such as tolbutamide, midazolam, and digoxin. However, there are also different views in the current study, such as the effect of AR on CYP3A4. To better understand the interactions of AR with drugs, we review the metabolic pathways and pharmacokinetic parameters of the main components of AR. Meanwhile, the regulatory effects and mechanisms of AR on DMEs and transporters are summarized to provide a theoretical and technical basis for the rational use of AR in clinical practice.

In vitro models to evaluate multidrug resistance in cancer cells: Biochemical and morphological techniques and pharmacological strategies

The overexpression of ATP-binding cassette (ABC) transporters contributes to the failure of chemotherapies and symbolizes a great challenge in oncology, associated with the adaptation of tumor cells to anticancer drugs such that these transporters become less effective, a mechanism known as multidrug resistance (MDR). The aim of this review is to present the most widely used methodologies for induction and comprehension of in vitro models for detection of multidrug-resistant (MDR) modulators or inhibitors, including biochemical and morphological techniques for chemosensitivity studies. The overexpression of MDR proteins, predominantly, the subfamily glycoprotein-1 (P-gp or ABCB1) multidrug resistance, multidrug resistance-associated protein 1 (MRP1 or ABCCC1), multidrug resistance-associated protein 2 (MRP2 or ABCC2) and cancer resistance protein (ABCG2), in chemotherapy-exposed cancer lines have been established/investigated by several techniques. Amongst these techniques, the most used are (i) colorimetric/fluorescent indirect bioassays, (ii) rhodamine and efflux analysis, (iii) release of 3,30-diethyloxacarbocyanine iodide by fluorescence microscopy and flow cytometry to measure P-gp function and other ABC transporters, (iv) exclusion of calcein-acetoxymethylester, (v) ATPase assays to distinguish types of interaction with ABC transporters, (vi) morphology to detail phenotypic characteristics in transformed cells, (vii) molecular testing of resistance-related proteins (RT-qPCR) and (viii) 2D and 3D models, (ix) organoids, and (x) microfluidic technology. Then, in vitro models for detecting chemotherapy MDR cells to assess innovative therapies to modulate or inhibit tumor cell growth and overcome clinical resistance. It is noteworthy that different therapies including anti-miRNAs, antibody-drug conjugates (to natural products), and epigenetic modifications were also considered as promising alternatives, since currently no anti-MDR therapies are able to improve patient quality of life. Therefore, there is also urgency for new clinical markers of resistance to more reliably reflect in vivo effectiveness of novel antitumor drugs.

Beyond endocrine resistance: estrogen receptor (ESR1) activating mutations mediate chemotherapy resistance through the JNK/c-Jun MDR1 pathway in breast cancer

PURPOSE

All patients with metastatic breast cancer (MBC) expressing estrogen receptor-α (ESR1) will eventually develop resistance to endocrine therapies. In up to 40% of patients, this resistance is caused by activating mutations in the ligand-binding domain (LBD) of ESR1. Accumulating clinical evidence indicate adverse outcomes for these patients, beyond that expected by resistance to endocrine therapy. Here we aimed to study the role of ESR1 mutations in conferring chemoresistance in BC cells.

METHODS

MCF-7 cells harboring Y537S and D538G ESR1 mutations (mut-ER) were employed to study the response to chemotherapy drugs, paclitaxel and doxorubicin, using viability and apoptotic assay in vitro, and tumor growth in vivo. JNK/c-Jun/MDR1 pathway was studied using qRT-PCR, western-blot, gene-reporter and ChIP assays. MDR1 expression was analyzed in clinical samples using IHC.

RESULTS

 Cell harboring ESR1 mutations displayed relative chemoresistance compared to WT-ER, evidenced by higher viability and reduced apoptosis as well as resistance to paclitaxel in vivo. To elucidate the underlying mechanism, MDR1 expression was examined and elevated levels were observed in mut-ER cells, and in clinical BC samples. MDR1 is regulated by the c-Jun pathway, and we showed high correlation between these two genes in BC using TCGA databases. Accordingly, we detected higher JNK/c-Jun expression and activity in ESR1-mutated cells, as well as increased occupancy of c-Jun in MDR1 promoter. Importantly, JNK inhibition decreased MDR1 expression and restored sensitivity to chemotherapy.

CONCLUSIONS

Taken together, these data indicate that ESR1 mutations confer chemoresistance through activation of the JNK/MDR1 axis. These finding suggest a novel treatment option for BC tumors expressing ESR1 mutations.

Effective Herbal Cocktail Strategies and Mechanisms in Cancer Treatment

Systematic treatment and cocktailed drug applications have become a paradigm shift for cancer therapy. This study aims to explore the highly potent herbal cocktail strategies and pharmacological mechanisms, by which herbal medicines are effective in cancer treatment. A total of 397 cases of clinically reported cancer treatments with pure herbs were scrutinized, and the herbal prescription rules were systematically analyzed. The core prescriptions and their pharmacological mechanisms were revealed. The results unveiled specific rules for effective herbal treatment of cancer, including boosting energy metabolism, inhibiting tumor proliferation, improving digestion and defecation, enhancing blood circulation, promoting gas exchange, and facilitating water and toxic substance metabolism. Pharmacologically, anti-cancer effects are achieved through the manipulation of PI3K-Akt, IL-17, HIF-1, VEGF, TNF, Wnt, and other pathways. Following this unfolded integrative prescription rule, herbal therapy demonstrated remarkable effects in clinical practices, from which a few representative cases are presented herein.

Low-intensity pulsed ultrasound combined with microbubble mediated JNK/c-Jun pathway to reverse multidrug resistance in triple-negative breast cancer

To investigate the effects of low-intensity pulsed ultrasound combined with microbubble (LIPUS-MB) mediated JNK/c-Jun pathway reversal on multidrug resistance in triple-negative breast cancer and the underlying mechanisms. An orthogonal experiment was designed to screen for the optimal parameters of LIPUS-MB in MDA-MB-231/DOX cells. The CCK-8 assay was used to determine the drug resistance of the cells and to measure their proliferation activity and resistance reversal efficiency at the optimal parameters. Hoechst 33,342 staining and Annexin V-FITC/PI staining were employed to detect cell morphological changes and apoptosis, respectively. The MDA-MB-231/DOX models of transplanted tumor were established in BALB/c. The impact of LIPUS-MB on allograft tumor growth was observed in vivo. Immunohistochemistry was employed to investigate the expression of P-gp, ABCG2, and Ki-67 in tumor tissues, while western blot was utilized to assess the protein expression of P-gp, ABCG2, JNK, p-JNK, c-Jun, p-c-Jun, Bcl-2 and Bax in both MDA-MB-231/DOX cells and allograft tumor tissues. The optimal LIPUS-MB parameters for MDA-MB-231/DOX cells are the microbubble concentration of 20%, ultrasound intensity of 1.0 W/cm2, and irradiation time of 60 s. The drug resistance index of MDA-MB-231/DOX cells is 19.17. Following the optimal parameter application, the IC50 value of the cells decreases by 5.71-fold, with a reversal efficiency of 87.03%, and a simultaneous decrease in cell proliferation activity. Compared with other groups, the DOX + LIPUS-MB group displayed the highest incidence of apoptotic nuclear morphology, and the greatest quantity of cellular apoptosis and the most pronounced decrease in the expression levels of P-gp, ABCG2, p-JNK, p-c-Jun, and Bcl-2 proteins within the cells. Conversely, the expression levels of Bax proteins reach the highest levels (all P < 0.05). Furthermore, in vivo subcutaneous tumor transplantation experiments in nude mice revealed that the DOX + LIPUS-MB group exhibited smaller tumor growth rate, volume and the expression of P-gp, ABCG2, and Ki-67 compared to the DOX + LIPUS group, indicating the most pronounced inhibitory effect on tumor growth and it significantly inhibited tumor proliferation, promoted its apoptosis. In conclusion, following parameter optimization, LIPUS-MB was found to reduce the drug resistance of MDA-MB-231/DOX cells. The underlying mechanism may involve the downregulation of P-gp and ABCG2 proteins expression through the modulation of the JNK/c-Jun pathway by LIPUS-MB, thereby inhibiting cell proliferation activity and promoting apoptosis, and enhancing the in vivo anti-tumor effect of DOX, thus reversing multidrug resistance in triple-negative breast cancer.

Research Progress on the Anti-Cancer Effects of Astragalus membranaceus Saponins and Their Mechanisms of Action

Astragalus membranaceus saponins are the main components of A. membranaceus, a plant widely used in traditional Chinese medicine. Recently, research on the anti-cancer effects of A. membranaceus saponins has received increasing attention. Numerous in vitro and in vivo experimental data indicate that A. membranaceus saponins exhibit significant anti-cancer effects through multiple mechanisms, especially in inhibiting tumor cell proliferation, migration, invasion, and induction of apoptosis, etc. This review compiles relevant studies on the anti-cancer properties of A. membranaceus saponins from various databases over the past two decades. It introduces the mechanism of action of astragalosides, highlighting their therapeutic benefits in the management of cancer. Finally, the urgent problems in the research process are highlighted to promote A. membranaceus saponins as an effective drug against cancer.

Protosappanin B enhances the chemosensitivity of 5-fluorouracil in colon adenocarcinoma by regulating the LINC00612/microRNA-590-3p/Golgi phosphoprotein 3 axis

BACKGROUND

5-fluorouracil (5-FU) is conventionally used in chemotherapy for colon adenocarcinomas. Acquired resistance of 5-FU remains a clinical challenge in colon cancer, and efforts to develop targeted agents to reduce resistance have not yielded success. Protosappanin B (PSB), the main component of Lignum Sappan extract, is known to exhibit anti-tumor effects. However, whether and how PSB could improve 5-FU resistance in colon cancer have not yet been established. In this study, we aimed to explore the effects and underlying mechanisms of PSB in 5-FU-induced chemoresistance in colon adenocarcinoma.

METHODS

Forty-seven paired colon cancer tissue samples from patients who received 5-FU chemotherapy were collected as clinical samples. Two 5-FU resistant colon cancer cell lines were established for in vitro experiments. Reverse transcription-quantitative PCR (RT-qPCR) was performed to determine the mRNA and microRNA (miRNA) expression levels in colon adenocarcinoma tissues and cell lines. Cell Counting Kit-8 (CCK-8) and flow cytometry assays were performed to evaluate cell proliferation and apoptosis, respectively.

RESULTS

LINC00612 was highly expressed in colon adenocarcinoma samples and 5-FU resistant colon cancer cells. LINC00612 knockdown enhances 5-FU chemosensitivity in 5-FU resistant cells. Notably, PSB treatment attenuated LINC00612 expression in 5-FU resistant colon adenocarcinoma cells. Moreover, PSB treatment reversed the increase in LINC00612-induced 5-FU resistance. Mechanistically, LINC00612 specifically bound to miR-590-3p, which promoted 5-FU resistance in colon adenocarcinoma cells and attenuated the inhibitory effect of LINC00612 on GOLPH3 expression.

CONCLUSION

PSB attenuates 5-FU chemoresistance in colon adenocarcinoma by regulating the LINC00612/miRNA-590-3p/GOLPH3 axis.

Determination of vericiguat in rat plasma by UPLC-MS/MS and its application to drug interaction

Vericiguat (VER) is a novel soluble guanylate cyclase stimulator treating symptomatic chronic heart failure (HF), and it is a substrate of both transporters P-glycoprotein and breast cancer resistance protein (BCRP). Astragaloside IV (ASIV) is the main active ingredient in Radix Astragali (Huangqi), a traditional Chinese medicine widely used for HF treatment in China. ASIV's effect on the protein expression of P-glycoprotein and BCRP has been observed, its impact on VER metabolism remain uncertain. In the present study, male Sprague-Dawley rats were administered with 20 mg/kg ASIV and 1 mg/kg VER to study their pharmacokinetics. Blood samples were subject to liquid-liquid extraction, and riociguat was employed as the internal standard (IS). The analytical method involved a C18 column (XSelect® HSS T3 column, 2.1 × 100 mm, 2.5 μm) with a mobile phase of 0.1% formic acid and acetonitrile for gradient elution. The flow rate of the mobile phase was set at 0.2 mL/min, and 5 µL of the sample was used for analysis. The positive ion multi-response monitoring mode was utilized with a transition of m/z 427.4→109.1 for VER and m/z 423.3→109.1 for the IS. The method exhibited good linearity within the concentration range of 0.1 to 300 ng/mL (r = 0.9987), and all the validation processes were conducted in accordance with the requirements of biological analysis. The pharmacokinetic results revealed that ASIV did not significantly alter the main parameters of VER, except for Cmax, which decreased by 33.2% (P < 0.05). Overall, our study successfully established a selective, sensitive and repeatable ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis for detecting VER in rat plasma.

Astragaloside IV, as a potential anticancer agent

Cancer is a global intractable disease, and its morbidity and mortality are increasing year by year in developing countries. Surgery and chemotherapy are often used to treat cancer, but they result in unsatisfactory outcomes, such as severe side effects and drug resistance. With the accelerated modernization of traditional Chinese medicine (TCM), an increasing body of evidence has shown that several TCM components have significant anticancer activities. Astragaloside IV (AS-IV) is considered the main active ingredient of the dried root of Astragalus membranaceus. AS-IV exhibits various pharmacological effects, such as anti-inflammatory, hypoglycemic, antifibrotic, and anticancer activities. AS-IV possesses a wide range of activities, such as the modulation of reactive oxygen species-scavenging enzyme activities, participation in cell cycle arrest, induction of apoptosis and autophagy, and suppression of cancer cell proliferation, invasiveness, and metastasis. These effects are involved in the inhibition of different malignant tumors, such as lung, liver, breast, and gastric cancers. This article reviews the bioavailability, anticancer activity, and mechanism of AS-IV and provides suggestions for further research of this TCM.

Research progress on the antitumor effects of astragaloside IV

One of the most important and effective components of Astragalus membranaceus is astragaloside IV (AS-IV), which can exert anti-tumor effects through various pathways. For instance, AS-IV exerts an anti-tumor effect by acting at the cellular level, regulating the phenotype switch of tumor-associated macrophages, or inhibiting the development of tumor cells. Furthermore, AS-IV inhibits tumor cell progression by enhancing its sensitivity to antitumor drugs or reversing the drug resistance of tumor cells. This article reviews the different mechanisms of AS-IV inhibition of epithelial-mesenchymal transition (EMT), migration, proliferation, and invasion of tumor cells, inducing apoptosis and improving the sensitivity of anti-tumor drugs. This review summarizes recent progress in the current research into AS-IV anti-tumor effect and provides insight on the next anti-tumor research of AS-IV.

Combining the Anticancer and Immunomodulatory Effects of Astragalus and Shiitake as an Integrated Therapeutic Approach

Astragalus root (Huang Qi) and Shiitake mushrooms (Lentinus edodes) are both considered medicinal foods and are frequently used in traditional Chinese medicine due to their anticancer and immunomodulating properties. Here, the scientific literatures describing evidence for the anticancer and immunogenic properties of Shiitake and Astragalus were reviewed. Based on our experimental data, the potential to develop medicinal food with combined bioactivities was assessed using Shiitake mushrooms grown over Astragalus beds in a proprietary manufacturing process, as a novel cancer prevention approach. Notably, our data suggest that this new manufacturing process can result in transfer and increased bioavailability of Astragalus polysaccharides with therapeutic potential into edible Shiitake. Further research efforts are required to validate the therapeutic potential of this new Hengshan Astragalus Shiitake medicinal food.

The study of Raddeanin A cerebrovascular endothelial cell trafficking through P-glycoprotein

As one of the natural triterpenoids isolated from Anemone Raddeana Regel, Raddeanin A (RA) has been confirmed to possess therapeutic effects against multiple tumorigeneses, especially for the onset of glioblastoma and growth in human brains. However, the mechanism by which this happens remains poorly understood in terms of the vascular endothelium trafficking routine of RA through the brain-blood barrier (BBB). To seek such answers, human brain microenvironment endothelial cells (HBMECs) were used to stimulate the microenvironment in vitro, and to explore the intracellular accumulation of RA. The results of this experiment illustrated that RA has a relative moderate transport affinity for such cells. The kinetic parameter K_m was 37.01 ± 2.116 μM and V_max was 9.412 ± 0.1375 nM/min/mg of protein. Interestingly, protein downregulation of P-glycoprotein (P-gp, ABCB1/MDR1) significantly activated RA transmembrane activity, which proves that P-gp is responsible for RA cellular trafficking. In addition, the selective non-specific inhibitor, LY335979 increased either RA or the classical substrate of P-gp, digoxin, intracellular accumulation by restricting the transporter's function but without jeopardizing cytomembrane proteins. Moreover, a decrease in the expression or activity of P-gp triggered RA drug resistance to HBMECs. In summary, our data showed that both the expression and function of P-gp are all necessary for RA transmembrane trafficking through cerebrovascular endothelial cells. This study provides significant evidence for the presence of a connection between RA transport and P-gp variation during drug BBB penetration. It is also suggesting some vital guidance on the RA pharmacodynamic effect in human brains.

5-Fluorouracil (5-FU) resistance and the new strategy to enhance the sensitivity against cancer: Implication of DNA repair inhibition

5-Fluorouracil (5-FU) has been an important anti-cancer drug to date. With an increase in the knowledge of its mechanism of action, various treatment modalities have been developed over the past few decades to increase its anti-cancer activity. But drug resistance has greatly affected the clinical use of 5-FU. Overcoming this chemoresistance is a challenge due to the presence of cancer stem cells like cells, cancer recurrence, metastasis, and angiogenesis. In this review, we have systematically discussed the mechanism of 5-FU resistance and advent strategies to increase the sensitivity of 5-FU therapy including resistance reversal. Special emphasis has been given to the cancer stem cells (CSCs) mediated 5-FU chemoresistance and its reversal process by different approaches including the DNA repair inhibition process.

Molecular mechanisms of astragaloside‑IV in cancer therapy (Review)

Radix Astragali (RA) is widely used in traditional Chinese medicine (TCM), and astragaloside IV (AS-IV) is the most critical component of RA. Previous studies have demonstrated that AS-IV exerts effects on the myocardium, nervous system and endocrine system, among others. In the present review article, data from studies conducted over the past 20 years were collated, which have evaluated the effects of AS-IV on tumors. The mechanisms of action of AS-IV on malignant cells both in vivo and in vitro were summarized and it was demonstrated that AS-IV plays a vital role, particularly in inhibiting tumor growth and metastasis, promoting the apoptosis of tumor cells, enhancing immune function and preventing drug resistance. Moreover, AS-IV controls several epithelial-mesenchymal transformation (EMT)-related and autophagy-related pathways, such as the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT), Wnt/β-catenin, mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK) and transforming growth factor-β (TGF-β)/SMAD signaling pathways, which are commonly affected in the majority of tumors. The present review provides new perspectives on the functions of AS-IV and its role as an adjuvant treatment in cancer chemotherapy.

Astragaloside IV derived from Astragalus membranaceus: A research review on the pharmacological effects

Decoctions prepared from the roots of Astragali Radix are known as "Huangqi" and are widely used in traditional Chinese medicine for treatment of viral and bacterial infections, inflammation, as well as cancer. Astragaloside IV (AS-IV), one of the major compounds from the aqueous extract of Astragalus membranaceus, is a cycloartane-type triterpene glycoside chemical. To date, many studies in cellular and animal models have demonstrated that AS-IV possesses potent protective effects in cardiovascular, lung, kidney and brain. Based on studies over the past several decades, this review systematically summarizes the pharmacological effects, pharmacokinetics and the toxicity of AS-IV. We analyze in detail the pharmacological effects of AS-IV on neuroprotection, liver protection, anti-cancer and anti-diabetes, attributable to its antioxidant, anti-inflammatory, anti-apoptotic properties, and the roles in enhancement of immunity, attenuation of the migration and invasion of cancer cells and improvement of chemosensitivity of chemotherapy drugs. In addition, the latest developments in the combination of AS-IV and other active ingredients of traditional Chinese medicine or chemical drugs are detailed. These pharmacological effects are associated with multiple signaling pathways, including the Raf-MEK-ERK pathway, EGFR-Nrf2 signaling pathway, Akt/PDE3B signaling pathway, AMPK signaling pathway, NF-κB signaling pathway, Nrf2 antioxidant signaling pathways, PI3K/Akt/mTOR signaling pathway, PKC-α-ERK1/2-NF-κB pathway, IL-11/STAT3 signaling pathway, Akt/GSK-3β/β-catenin pathway, JNK/c-Jun/AP-1 signaling pathway, PI3K/Akt/NF-κB pathway, miRNA-34a/LDHA pathway, Nox4/Smad2 pathway, JNK pathway and NF-kB/PPARγ pathway. This review will provide an overall understanding of the pharmacological functions of astragaloside IV on neuroprotection, liver protection, anti-cancer and anti-diabetes. In light of this, AS-IV will be a potent alternative therapeutic agent for treatment of the above mentioned diseases.

Astragaloside IV regulates NF-κB-mediated cellular senescence and apoptosis of hepatic stellate cells to suppress PDGF-BB-induced activation

Activated hepatic stellate cells (HSCs) are the principal effectors during hepatic fibrosis, which is characterized by the accumulation of extracellular matrix. Therefore, present therapies and investigations into hepatic fibrosis mainly focus on the suppression of activated HSCs. Astragaloside IV (ASIV) is an effective constituent extracted from the plant Astragalus membranaceus and has exhibited anti-fibrotic properties in hepatic fibrosis. However, its protective mechanism against hepatic fibrosis is not fully understood. The present study aimed to investigate the mechanistic role of ASIV on rat HSC-T6 cells activated with platelet-derived growth factor (PDGF)-BB. HSC-T6 cells were activated using PDGF-BB and subsequently treated with ASIV (final concentrations of 20 and 40 µg/ml) for 48 h. ASIV treatment decreased the expression of α1 type I collagen, α-smooth muscle actin and fibronectin on mRNA and protein levels, suggesting that ASIV suppresses PDGF-BB-induced HSC-T6 activation. Senescence-associated β-galactosidase activity, p21, high-mobility group AT-hook 1 and p53, common biomarkers of senescence, were upregulated by ASIV treatment. In addition, the expression of telomerase reverse transcriptase was reduced. ASIV promoted apoptosis of PDGF-BB-activated HSC-T6 cells. The NF-κB signaling pathway, which controls cellular senescence and apoptosis, was demonstrated to be stimulated by ASIV by increasing p65, p52, p50 and inhibitor of NF-κB kinase α expression levels, and by suppressing the expression of NF-κB inhibitor α. Taken together, these results demonstrated that ASIV promoted cellular senescence and apoptosis by activating the NF-κB pathway to suppress PDGF-BB-induced HSC-T6 activation; with potential implications for the treatment of hepatic fibrosis.

Reduced expression of annexin A1 promotes gemcitabine and 5-fluorouracil drug resistance of human pancreatic cancer

Intrinsic chemoresistance is the main reason for the failure of human pancreatic ductal adenocarcinoma (PDAC) therapy. To identify the candidate protein, we compared the protein expression profiling of PDAC cells and its distinct surviving cells following primary treatment with gemcitabine (GEM) and 5-fluorouracil (5-FU) by two-dimensional electrophoresis combined with liquid chromatography-mass spectrometry or mass spectrometry. A total of 20 differentially expressed proteins were identified, and annexin A1 (ANXA1) was analyzed for further validation. The functional validation showed that the downregulation of ANXA1 contributes to GEM and 5-FU resistance in PDAC cells through protein kinase C/c-Jun N-terminal kinase/P-glycoprotein signaling pathway. Our findings provide a platform for the further elucidation of the underlying mechanisms of PDAC intrinsic chemoresistance and demonstrated that ANXA1 may be a valid marker for anticancer drug development.

Inhibitory effects of cycloastragenol on abdominal aortic aneurysm and its related mechanisms

BACKGROUND AND PURPOSE

Abdominal aortic aneurysm (AAA) is a degenerative disease affecting human health, but there are no safe and effective medications for AAA therapy. Cycloastragenol (CAG), derived from Astragali Radix, has various pharmacological effects. However, whether CAG can protect against AAA remains elusive. In this study, we investigated whether CAG has an inhibitory effect on AAA and its related mechanism.

EXPERIMENTAL APPROACH

The AAA mouse model was induced by incubating the abdominal aorta with elastase. CAG was administered by gavage at different doses beginning on the same day or 14 days after inducing AAA to explore its preventive or therapeutic effects respectively. The preventive effects of CAG on AAA were verified in another AAA mouse model induced by angiotensin II in ApoE-/- mouse. In vitro experiments were implemented on rat vascular smooth muscle cells (VSMCs) stimulated by TNF-α.

KEY RESULTS

Compared to the control AAA model group, CAG (125 mg·kg-1 body weight day-1 ) reduced the incidence of AAA, the dilatation of aorta and elastin degradation in media in both mouse models of AAA. CAG suppressed the inflammation, oxidation, phenotype switch and apoptosis in TNF-α-stimulated VSMCs, ameliorated the expression and activity of MMPs and decreased the activation of the ERK/JNK signalling pathway. CAG also inhibited the degradation of elastin in TNF-α-stimulated VSMCs.

CONCLUSION AND IMPLICATIONS

CAG presents protective effects against AAA through down-regulation of the MAPK signalling pathways and thus attenuates inflammation, oxidation, VSMC phenotype switch and apoptosis and the expression of MMPs as well as increasing elastin biosynthesis.