Anti-angiogenic effects of Siegesbeckia glabrescens are mediated by suppression of the Akt and p70S6K-dependent signaling pathways

Broussonin A- and B-mediated inhibition of angiogenesis by blockade of VEGFR-2 signalling pathways and integrin β1 expression

In the present study, we demonstrate the regulatory effects and mechanism of broussonin A and B, diphenylpropane derivatives isolated from Broussonetia kazinoki, on vascular endothelial growth factor‐A (VEGF‐A)–stimulated endothelial cell responses in vitro and microvessel sprouting ex vivo. Treatment with broussonin A or B suppressed VEGF‐A‐stimulated endothelial cell proliferation by regulating the expression of cell cycle–related proteins and the phosphorylation status of retinoblastoma protein. In addition, treatment with broussonin A or B abrogated VEGF‐A‐stimulated angiogenic responses including endothelial cell migration, invasion, tube formation and microvessel formation from rat aortic rings. These anti‐angiogenic activities of broussonin A and B were mediated through inactivation of VEGF‐A‐stimulated downstream signalling pathways, localization of vascular endothelial‐cadherin at cell‐cell contacts, and down‐regulation of integrin β1 and integrin‐liked kinase. Furthermore, treatment with broussonin A or B inhibited proliferation and invasion of non–small cell lung cancer and ovarian cancer cells. Taken together, our findings suggest the pharmacological potential of broussonin A and B in the regulation of angiogenesis, cancer cell growth and progression.

Herba Siegesbeckiae: A review on its traditional uses, chemical constituents, pharmacological activities and clinical studies

ETHNOPHARMACOLOGICAL RELEVANCE

Herba Siegesbeckiae, mainly includes Sigesbeckia orientalis L, Sigesbeckiae pubescens Makino and Sigesbeckiae glabrescens Makino. Herba Siegesbeckiae, also known as 'Xi-Xian Cao' (Chinese: ), has been regarded as an important traditional Chinese medicine since Tang dynasty. The dried aerial parts of Herba Siegesbeckiae are also being used as a herbal medicine in many countries such as Japan, Korea and Vietnam. In China, Herba Siegesbeckiae has been used for the treatment of rheumatic arthralgia with aching and weakness of loins and knees, as well as numbness of limbs.

AIM OF THIS REVIEW

The aim of this review was to provide critical analysis on the scientific evidence to support the traditional uses of Herba Siegesbeckiae. The information available on its in botanical characteristics, traditional uses, chemical constituents, pharmacological activities, clinical studies, toxicity and quality control was summarized to understand the current research and provided the leas for future study.

MATERIALS AND METHODS

The search terms "Herba Siegesbeckiae", "Sigesbeckia orientalis", "Sigesbeckia pubscens" and "Sigesbeckia glabrescens" were used to obtain the information from electronic databases such as Web of Science, China National Knowledge Infrastructure, PubMed, Google Scholar and SciFinder Scholar and other web search instruments (Springer, Yahoo search). The information provided in this review was based on peer-reviewed papers in English and Chinese. Besides, information was also collected from ancient documents.

RESULT

The studies showed that Herba Siegesbeckiae contains sesquiterpenoids, diterpenoids, flavonoids and organic acids, etc. Due to these constituents, it displayed numerous pharmacological activities, such as anti-inflammatory, antitumor, antiallergic, antioxidant, antithrombotic and antibacterial activities. In addition, it showed effects in protecting myocardial and cerebral ischemia injury.

CONCLUSIONS

According to its traditional uses, chemical constituents, pharmacological activities and clinic studies, Herba Siegesbeckiae is regarded as a promising medical plant with various chemical compounds and numerous pharmacological activities. However, fewer experimental studies were focused on toxicity and quantitative study of 3 species. It suggested that further in-depth study of toxicity and quality control were critical for future evaluation of drug efficacy and safety.

Antioxidant Compounds, Kirenol and Methyl ent-16α, 17-dihydroxy-kauran-19-oate Bioactivity-Guided Isolated from Siegesbeckia glabrescens Attenuates MITF-Mediated Melanogenesis via Inhibition of Intracellular ROS Production

Siegesbeckia glabrescens (Compositae), an annual herb indigenous to Korean mountainous regions and has been eaten as a food in Korea. This study investigated ABTS, DPPH and nitric oxide (NO) radical-scavenging activities, and melanin production and TYR inhibitory effects-guided fractionation to identify therapeutic phytochemicals from S. glabrescens that can attenuate oxidation and melanogenesis in murine melanoma B16F10 cells. Nine compounds with inhibitory effects on melanin production, and TYR activity, and ABTS, DPPH, and NO radical scavenging activity were isolated from the 100% ethanol fraction from S. glabrescens. Among the nine compounds, kirenol (K), methyl ent-16α, 17-dihydroxy-kauran-19-oate (MDK) had strong inhibitory effects on melanin production and TYR activity with antioxidant effects. Western blot analysis revealed that K and MDK suppressed tyrosinase-related protein (TYRP)-1, TYRP-2 and microphthalmia-associated transcription factor (MITF) expression. Moreover, these two compounds inhibited intracellular reactive oxygen species (ROS) level in tert-butyl hydroperoxide (t-BHP)-treated B16F10 cells. Our results suggest that S. glabrescens containing active compounds such as K and MDK, which has antioxidant and antimelanogenesis effects, is the potent therapeutic and functional material for the prevention of oxidation-induced hyperpigmentation.

New oxylipins from Siegesbeckia glabrescens as potential antibacterial agents

Seven rare oxylipins, siegesbeckins A-G (1-7) representing further bioactive constituents different from the general terpenyl compounds found in Siegesbeckia species, have been obtained from the aerial parts of Siegesbeckia glabrescens. These isolates were identified to be a series of methyl 4-methylpentanoates incorporating fatty acid moieties of different chain lengths, based on spectroscopic techniques, and their absolute configurations were determined via chemical degradation and comparison of experimental and theoretically calculated ECD spectra. With respect to bioactivity, antibacterial, anti-inflammatory and cytotoxic properties of selected compounds were evaluated. Compounds 1 and 5 showed moderate antibacterial activity against two Gram-positive bacteria with MIC values of 4.3 μg/mL, while 3 showed no pronounced activity in these assays.

Novel functions for 2-phenylbenzimidazole-5-sulphonic acid: Inhibition of ovarian cancer cell responses and tumour angiogenesis

In this study, we investigated the effects and molecular mechanisms of 2-phenylbenzimidazole-5-sulphonic acid (PBSA), an ultraviolet B protecting agent used in sunscreen lotions and moisturizers, on ovarian cancer cell responses and tumour angiogenesis. PBSA treatment markedly blocked mitogen-induced invasion through down-regulation of matrix metalloproteinase (MMP) expression and activity in ovarian cancer SKOV-3 cells. In addition, PBSA inhibited mitogen-induced cell proliferation by suppression of cyclin-dependent kinases (Cdks), but not cyclins, leading to pRb hypophosphorylation and G1 phase cell cycle arrest. These anti-cancer activities of PBSA in ovarian cancer cell invasion and proliferation were mediated by the inhibition of mitogen-activated protein kinase kinase 3/6-p38 mitogen-activated protein kinase (MKK3/6-p38MAPK ) activity and subsequent down-regulation of MMP-2, MMP-9, Cdk4, Cdk2 and integrin β1, as evidenced by treatment with p38MAPK inhibitor SB203580. Furthermore, PBSA suppressed the expression and secretion of vascular endothelial growth factor in SKOV-3 cells, leading to inhibition of capillary-like tubular structures in vitro and angiogenic sprouting ex vivo. Taken together, our results demonstrate the pharmacological effects and molecular targets of PBSA on modulating ovarian cancer cell responses and tumour angiogenesis, and suggest further evaluation and development of PBSA as a promising chemotherapeutic agent for the treatment of ovarian cancer.

Long non-coding RNA UBE2CP3 enhances HCC cell secretion of VEGFA and promotes angiogenesis by activating ERK1/2/HIF-1α/VEGFA signalling in hepatocellular carcinoma

Background

Angiogenesis is considered as an important process in the development of malignancies and is associated with cancer progression and metastasis. Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver and is recognized as a typical angiogenic tumor. Thus, it is of great importance to study the underlying mechanism of angiogenesis in HCC. The long non-coding RNA (lncRNA) ubiquitin conjugating enzyme E2C pseudogene 3 (UBE2CP3) has been reported as an oncogene that promotes tumor metastasis in HCC. However, the role and underlying mechanisms of UBE2CP3 in HCC angiogenesis are still unclear.

Methods

We measured the expression levels of UBE2CP3 by in situ hybridization (ISH) and quantitative real-time polymerase chain reaction (qRT-PCR) in HCC patient samples. We also concomitantly used CD31/PAS double-staining to measure endothelial vessel (EV) density and used qRT-PCR to measure the CD31 mRNA level. HepG2 and SMMC-7721 cells were transfected with Lv-UBE2CP3 or Sh-UBE2CP3 virus to obtain stably over-expressing or knocking-down UBE2CP3 cell lines. The indirect effects of UBE2CP3 on ECs were studied by establishing a co-culture system using Transwell chambers with a 0.4-μm pore size. HCC cells and ECs in the co-culture system were separated, but the cytokines and growth factors were able to communicate with each other. Following exposed to HCC cells, ECs were collected for functional studies. Finally, we studied the function of UBE2CP3 in vivo by chick embryo chorioallantoic membrane (CAM) angiogenesis assays and nude mouse tumorigenicity assays.

Results

In this study, we found that UBE2CP3 expression was higher in HCC tissues than in para-tumor tissues and was up-regulated in tissues with high EV density. Functionally, we found that in the co-culture systems, HCC cells overexpressing UBE2CP3 promoted HUVEC proliferation, migration and tube formation via the activation of ERK/HIF-1α/p70S6K/VEGFA signalling, increasing the level of VEGFA in HCC cell supernatant. In addition, the opposite results appeared when the expression of UBE2CP3 in HCC cells was knocked down. Consistent with these results, CAM angiogenesis assays and nude mouse tumorigenicity assays showed that UBE2CP3 expression up-regulated EV density in vivo.

Conclusion

Our study suggests that UBE2CP3 can enhance the interaction between HCC tumor cells and HUVECs and promote HCC tumorigenicity by facilitating angiogenesis.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0727-1) contains supplementary material, which is available to authorized users.

5-Caffeoylquinic acid inhibits invasion of non-small cell lung cancer cells through the inactivation of p70S6K and Akt activity: Involvement of p53 in differential regulation of signaling pathways

In the present study, we investigated the effects and molecular mechanism of 5-caffeoylquinic acid (5-CQA), a natural phenolic compound isolated from Ligularia fischeri, on cell invasion, proliferation and adhesion in p53 wild-type A549 and p53-deficient H1299 non-small cell lung cancer (NSCLC) cells. 5-CQA abrogated mitogen-stimulated invasion, but not proliferation, in both A549 and H1299 cells. In addition, 5-CQA inhibited mitogen-stimulated adhesion in A549 cells only. Anti-invasive activity of 5-CQA in A549 cells was mediated by the inactivation of p70(S6K)-dependent signaling pathway. In contrast, in H1299 cells the inactivation of Akt was found to be involved in 5-CQA-mediated inhibition of cell invasion. Collectively, these findings demonstrate the pharmacological roles and molecular targets of 5-CQA in regulating NSCLC cell fate, and suggest further evaluation and development of 5-CQA as a potential therapeutic agent for the treatment and prevention of lung cancer.

Ligularia fischeri inhibits endothelial cell proliferation, invasion and tube formation through the inactivation of mitogenic signaling pathways and regulation of vascular endothelial cadherin distribution and matrix metalloproteinase expression

Ligularia fischeri (LF) has been used as an edible herb and traditional medicine for the treatment of inflammatory and infectious diseases. In the present study, we report the effects and molecular mechanism of the ethanolic extract of LF on cell proliferation, invasion and tube formation in human umbilical vein endothelial cells (HUVECs). LF-mediated inhibition of cell proliferation was accompanied by reduced expression of cell cycle-related proteins such as cyclin-dependent kinases (Cdks) and cyclins, leading to pRb hypophosphorylation and G1 phase cell cycle arrest. We also show that LF treatment inhibited cell invasion and tube formation in HUVECs. These anti-angiogenic activities of LF were associated with the inactivation of mitogenic signaling pathways, induction of vascular endothelial (VE)-cadherin distribution at cell-cell contacts and inhibition of matrix metalloproteinase (MMP) expression. Collectively, our findings demonstrate the pharmacological functions and molecular mechanisms of LF in regulating endothelial cell fates, and support further development as a potential therapeutic agent for the treatment and prevention of angiogenesis-related disorders including cancer.