Paeonol oxime inhibits bFGF-induced angiogenesis and reduces VEGF levels in fibrosarcoma cells

Paeonol repurposing for cancer therapy: From mechanism to clinical translation

Paeonol (PAE) is a natural phenolic monomer isolated from the root bark of Paeonia suffruticosa that has been widely used in the clinical treatment of some inflammatory-related diseases and cardiovascular diseases. Much preclinical evidence has demonstrated that PAE not only exhibits a broad spectrum of anticancer effects by inhibiting cell proliferation, invasion and migration and inducing cell apoptosis and cycle arrest through multiple molecular pathways, but also shows excellent performance in improving cancer drug sensitivity, reversing chemoresistance and reducing the toxic side effects of anticancer drugs. However, studies indicate that PAE has the characteristics of poor stability, low bioavailability and short half-life, which makes the effective dose of PAE in many cancers usually high and greatly limits its clinical translation. Fortunately, nanomaterials and derivatives are being developed to ameliorate PAE's shortcomings. This review aims to systematically cover the anticancer advances of PAE in pharmacology, pharmacokinetics, nano delivery systems and derivatives, to provide researchers with the latest and comprehensive information, and to point out the limitations of current studies and areas that need to be strengthened in future studies. We believe this work will be beneficial for further exploration and repurposing of this natural compound as a new clinical anticancer drug.

Pharmacological effects and mechanisms of paeonol on antitumor and prevention of side effects of cancer therapy

Cancer represents one of the leading causes of mortality worldwide. Conventional clinical treatments include radiation therapy, chemotherapy, immunotherapy, and targeted therapy. However, these treatments have inherent limitations, such as multidrug resistance and the induction of short- and long-term multiple organ damage, ultimately leading to a significant decrease in cancer survivors' quality of life and life expectancy. Paeonol, a nature active compound derived from the root bark of the medicinal plant Paeonia suffruticosa, exhibits various pharmacological activities. Extensive research has demonstrated that paeonol exhibits substantial anticancer effects in various cancer, both in vitro and in vivo. Its underlying mechanisms involve the induction of apoptosis, the inhibition of cell proliferation, invasion and migration, angiogenesis, cell cycle arrest, autophagy, regulating tumor immunity and enhanced radiosensitivity, as well as the modulation of multiple signaling pathways, such as the PI3K/AKT and NF-κB signaling pathways. Additionally, paeonol can prevent adverse effects on the heart, liver, and kidneys induced by anticancer therapy. Despite numerous studies exploring paeonol's therapeutic potential in cancer, no specific reviews have been conducted. Therefore, this review provides a systematic summary and analysis of paeonol's anticancer effects, prevention of side effects, and the underlying mechanisms involved. This review aims to establish a theoretical basis for the adjunctive strategy of paeonol in cancer treatment, ultimately improving the survival rate and enhancing the quality of life for cancer patients.

Combination of ShuangDan Capsule and Sorafenib Inhibits Tumor Growth and Angiogenesis in Hepatocellular Carcinoma Via PI3K/Akt/mTORC1 Pathway

Hepatocellular carcinoma (HCC) is a high mortality liver cancer. The existing treatments (transplantation, chemotherapy, and individualized treatment) with limitations. However, drug combination provides a viable option for hepatocellular carcinoma treatment. A Chinese patent medicine, ShuangDan Capsules (SDC), has been clinically prescribed to hepatocellular carcinoma patients as adjuvant therapy and has shown good antitumor activity. The purpose of this study was to investigate whether SDC could improve the anti-cancer effect and mitigate adverse reactions of sorafenib on HCC in vivo. Magnetic resonance imaging (MRI), immunohistochemistry, and western blot were executed to reveal the potential mechanisms of the combination of SDC and sorafenib on HCC. Tumors appeared hyperintense on T2 sequence images relative to the adjacent normal liver in MRI. Combination of SDC and sorafenib inhibited the progression of DEN (Diethylnitrosamine)-induced HCC. In the HepG2 xenografts model, sorafenib plus SDC exhibited greater suppression on tumor growth than individual treatment accompanied with decreased expression of VEGF, VEGFA, Ki67, CD31 and increased expression of caspase-3. Furthermore, PI3K/Akt/mTORC1 pathway was inhibited by co-administration. Sorafenib monotherapy elicited hepatotoxicity for specific expression in the up-regulated level of aspartate transaminase (AST) and AST/glutamic-pyruvic transaminase (ALT) ratio, but the co-administration could remedy this adverse effect. These dates indicated that the combination of SDC and sorafenib might offer a potential therapy for HCC.

Paeonol Suppresses Vasculogenesis Through Regulating Vascular Smooth Muscle Phenotypic Switching

OBJECTIVE

Smooth muscle cell (SMC) phenotypic switching is associated with development of a variety of occlusive vascular diseases. Paeonol has been reported to be involved in suppressing SMC proliferation. However, it is still unknown whether paeonol can regulate SMC phenotypic switching, and which eventually result in suppressing vasculogenesis.

METHODS

Murine left common carotid artery was injured by completely ligation, and paeonol was administrated by intraperitoneal injection. Hematoxylin and eosin (H&E) staining was performed to visualize vascular neointima formation. Rat aortic SMCs were used to determine whether paeonol suppresses cell proliferation and migration. And murine hind limb ischemia model was performed to confirm the function role of paeonol in suppressing vasculogenesis.

RESULTS

Complete ligation of murine common carotid artery successfully induced neointima formation. Paeonol treatment dramatically reduced the size of injury-induced neointima. Using rat aortic primary SMC, we identified that paeonol strongly suppressed cell proliferation, migration, and decreased extracellular matrix deposition. And paeonol treatment dramatically suppressed vasculogenesis after hind limb ischemia injury.

CONCLUSION

Paeonol could regulate SMC phenotypic switching through inhibiting proliferation and migration of SMC, which results in inhibiting ischemia-induced vasculogenesis.

Guizhi Fuling Wan reduces autophagy of granulosa cell in rats with polycystic ovary syndrome via restoring the PI3K/AKT/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Guizhi Fuling Wan (GFW) is a traditional Chinese medicine used to remove blood stasis and dissipate phlegm for treating gynecological diseases that was invented by Zhang Zhongjing in the Eastern Han dynasty. In recent years, GFW has been widely used to treat patients with polycystic ovary syndrome (PCOS). Clinical and animal studies have shown that it is effective in the treatment of PCOS, but its mechanism is unknown. Generally, it works by regulating autophagy via the PI3K/AKT/mTOR signaling pathway.

AIM OF THE STUDY

This study investigated the effects and mechanism of GFW in PCOS rats with insulin resistance (IR) in order to provide better understanding of its observed clinical effects and a theoretical basis for the study of traditional Chinese medicine.

MATERIALS AND METHODS

Eighty-four female Sprague-Dawley rats were randomly divided into seven groups (n = 12 per group): 1) control, 2) PCOS model, 3) low-dose GFW, 4) medium-dose GFW, 5) high-dose GFW, 6) metformin, and 7) medium-dose GFW plus LY294002. In all non-control groups, we induced PCOS through daily letrozole combined with intragastric high-fat emulsion for 21 days. After treatment, rats were sacrificed and serum follicle-stimulating hormone (FSH), testosterone (T), progesterone, luteinizing hormone (LH), 17β-estradiol, fasting insulin (FINS), and fasting plasma glucose levels were measured by enzyme-linked immunosorbent assay (ELISA). The LH/FSH ratios and HOMA-IR values were calculated. Ovarian morphology was observed by hematoxylin and eosin staining, and all follicles were counted under a microscope. MDC-positive vesicles were used as markers to detect autophagy, and the expression levels of p62, Beclin1, and LC3-II were examined by immunostaining. Western blotting was used to measure PI3K/AKT/mTOR pathway activation, granulosa cell apoptosis, and autophagy.

RESULTS

Compared with the PCOS model group, GFW-treated rats had less atretic and cystic follicles, and more mature follicles and corpus lutea. The GFW-treated rats had lower serum T, LH, and FINS levels than the PCOS model group, as well as lower LH/FSH ratios and HOMA-IR values. GFW treatment resulted in significantly reduced levels of cleaved-Caspase-3, cleaved-Caspase-9, BAX, Beclin1, Atg5, and LC3-II. Phosphorylation of PI3K, AKT, and mTOR was significantly higher in GFW-treated rats compared with the PCOS model group. The phosphorylation of PI3K, AKT, and mTOR was decreased with the use of a PI3K antagonist.

CONCLUSIONS

Our results indicate that GFW inhibited granulosa cell autophagy and promoted follicular development to attenuate ovulation disorder in PCOS-IR rats. This was associated with activation of the PI3K/AKT/mTOR signaling pathway.

Microvascular Density, Endothelial Area, and Ki-67 Proliferative Index Correlate Each Other in Cat Post-Injection Fibrosarcoma

Soft tissue sarcomas are a large group of different tumor types both in humans and in animals. Among them, fibrosarcoma is the most frequent malignant mesenchymal tumoral form in cats, representing up to 28% of all cat skin tumors, while human fibrosarcoma, fortunately, only represents 5% of all sarcomas and 0.025% of the world-wide burden of tumors. This low incidence in humans leads to consideration of this group of tumoral diseases as rare, so therapeutic options are few due to the difficulty of starting clinical trials. In this context, the identification of research models for fibrosarcomas could be of great interest to deepen knowledge in this field and recognize new or possible biological pathways involved in tumor progression and metastasis. Angiogenesis is considered a fundamental scattering cause of tumor aggressiveness and progression in all forms of cancer, but only a few research parameters were developed and reported to express them quantitatively and qualitatively. The role in angiogenesis of microenvironmental stromal cells, such as fibroblasts, lymphocytes, mast cells, and macrophages, was largely demonstrated since this topic was first approached, while quantification of new vessels and their blood capacity in tumoral area is a relatively recent approach that could be well developed thanks to expertise in immunohistochemistry and image analysis. In this paper, a crossing study evaluating microvascular density (MVD), endothelial area (EA), and Ki-67 proliferative index was reported for a series of formalin-fixed and paraffin-embedded tissue samples from 99 cat patients, affected by cat post-injection fibrosarcoma, by using a till ×400 magnification light microscopy. We aim to demonstrate that cat pets may be considered a useful animal model for better studying the correspondent human diseases and we report, for the first time to our knowledge, experimental data in terms of correlation among MVD, EA, and Ki-67 strictly involved in aggressiveness and tumoral progression.

Paeonol Derivatives and Pharmacological Activities: A Review of Recent Progress

Paeonol, 2-hydroxy-4-methoxy acetophenone, is one of the main active ingredients of traditional Chinese medicine such as Cynanchum paniculatum, Paeonia suffruticosa Andr and Paeonia lactiflora Pall. Modern medical research has shown that paeonol has a wide range of pharmacological activities. In recent years, a large number of studies have been carried out on the structure modification of paeonol and the mechanism of action of paeonol derivatives has been studied. Some paeonol derivatives exhibit good pharmacological activities in terms of antibacterial, anti-inflammatory, antipyretic analgesic, antioxidant and other pharmacological effects. Herein, the research progress on paeonol derivatives and their pharmacological activities were systematically reviewed.

A novel organic cation transporter involved in paeonol transport across the inner blood-retinal barrier and changes in uptake in high glucose conditions

Paeonol exerts various pharmacological effects owing to its antiangiogenic, antioxidant, and antidiabetic activities. We aimed to investigate the transport mechanism of paeonol across the inner blood-retinal barrier both in vitro and in vivo. The carotid artery single injection method was used to investigate the retina uptake index of paeonol. The retina uptake index (RUI) value of [³H]paeonol was dependent on both concentration and pH. This value decreased significantly in the presence of imperatorin, tramadol, and pyrilamine when compared to the control. However, para-aminohippuric acid, choline, and taurine had no effect on the RUI value. Conditionally immortalized rat retina capillary endothelial cells (TR-iBRB cell lines) were used as an in vitro model of the inner blood-retinal barrier (iBRB). The uptake of [³H]paeonol by the TR-iBRB cell lines was found to be time-, concentration-, and pH-dependent. However, the uptake was unaffected by the absence of sodium or by membrane potential disruption. Moreover, in vitro structural analog studies revealed that [³H]paeonol uptake was inhibited in the presence of organic cationic compounds including imperatorin, clonidine and tramadol. This is consistent with the results obtained in vivo. In addition, transfections with OCTN1, 2 or plasma membrane monoamine transporter (PMAT) small interfering RNA did not affect paeonol uptake in TR-iBRB cell lines. Upon pre-incubation of these cell lines with high glucose (HG) media, [³H]paeonol uptake decreased and mRNA expression levels of angiogenetic factors, such as hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) increased. However, after the pretreatment of unlabeled paeonol in HG conditions, the mRNA levels of VEGF and HIF-1 were comparatively reduced, and the [³H]paeonol uptake rate was restored. After being exposed to inflammatory conditions induced by glutamate, TNF-α, and LPS, paeonol and propranolol pretreatment significantly increased the uptake of both [³H]paeonol and [³H]propranolol in TR-iBRB cell lines compared to their respective controls. Our results demonstrate that the transport of paeonol to the retina across the iBRB may involve the proton-coupled organic cation antiporter system, and the uptake of paeonol is changed by HG conditions.

Paeonol Inhibits Pancreatic Cancer Cell Migration and Invasion Through the Inhibition of TGF-β1/Smad Signaling and Epithelial-Mesenchymal-Transition

Purpose

Paeonol, a natural product derived from the root of Cynanchum paniculatum (Bunge) K. Schum and the root of Paeonia suffruticosa Andr. (Ranunculaceae) has attracted extensive attention for its anti-cancer proliferation effect in recent years. The present study examined the role of paeonol in suppressing migration and invasion in pancreatic cancer cells by inhibiting TGF-β1/Smad signaling.

Methods

Cell viability was evaluated by MTT and colonial formation assay. Migration and invasion capabilities were examined by cell scratch-wound healing assay and the Boyden chamber invasion assay. Western Blot and qRT-PCR were used to measure the protein and RNA levels of vimentin, E-cadherin, N-cadherin, and TGF-β1/Smad signaling.

Results

At non-cytotoxic dose, 100 μΜ and 150 μΜ of paeonol showed significant anti-migration and anti-invasion effects on Panc-1 and Capan-1 cells (p<0.01). Paeonol inhibited epithelial-mesenchymal-transition by upregulating E-cadherin, and down regulating N-cadherin and vimentin expressions. Paeonol inhibited TGF-β1/Smad signaling pathway by downregulating TGF-β1, p-Smad2/Smad2 and p-Smad3/Smad3 expressions. Further, TGF-β1 attenuated the anti-migration and anti-invasion capacities of paeonol in Panc-1 and Capan-1 cells.

Conclusion

These findings revealed that paeonol could suppress proliferation and inhibit migration and invasion in Panc-1 and Capan-1 cells by inhibiting the TGF-β1/Smad pathway and might be a promising novel anti-pancreatic cancer drug.

Beneficial Effects Exerted by Paeonol in the Management of Atherosclerosis

Atherosclerosis, a chronic luminal stenosis disorder occurred in large and medium arteries, is the principle pathological basis of cardiovascular diseases with the highest morbidity and mortality worldwide. In oriental countries, traditional Chinese medicine Cortex Moutan has been widely used for the treatment of atherosclerosis-related illnesses for thousands of years. Paeonol, a bioactive monomer extracted from Cortex Moutan, is an important pharmacological component responsible for the antiatherosclerotic effects. Numerous lines of findings have established that paeonol offers beneficial roles against the initiation and progression of atherosclerotic lesions through inhibiting proatherogenic processes, such as endothelium damage, chronic inflammation, disturbance of lipid metabolism, uncontrolled oxidative stress, excessive growth, and mobilization of vascular smooth muscle cells as well as abnormality of platelet activation. Investigations identifying the atheroprotective effects of paeonol present substantial evidence for potential clinical application of paeonol as a therapeutic agent in atherosclerosis management. In this review, we summarize the antiatherosclerotic actions by which paeonol suppresses atherogenesis and provide newly insights into its atheroprotective mechanisms and the future clinical practice.

Paeonol enhances the sensitivity of human ovarian cancer cells to radiotherapy-induced apoptosis due to downregulation of the phosphatidylinositol-3-kinase/Akt/phosphatase and tensin homolog pathway and inhibition of vascular endothelial growth factor

Radiotherapy is a vital and effective method to treat solid tumors. However, in many tumor types, development of resistance of cancer cells and cytotoxicity in normal tissues presents a major therapeutic problem. It is therefore crucial to identify and develop novel sensitizing agents that may improve the response to radiation therapy without causing any adverse effects. The present study aimed to investigate whether paeonol, a bioactive flavonoid, was able to confer sensitivity to radiation in human ovarian cancer cells. The human ovarian cancer cell lines SKOV-3 and OVCAR-3 were exposed to varying doses of radiation (2, 4 or 6 Gy) in the presence or absence of paeonol (25, 50 or 100 µM). Radiosensitivity was assessed by measuring cell viability using a CCK-8 assay and Annexin V/PI staining. Expression of vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α), proteins of the phosphatidylinositol-3-kinase (PI3K)/Akt pathway and apoptotic pathway proteins [caspase-3, Bcl-2-associated death promoter, B-cell lymphoma (Bcl)-2, Bcl-2-associated X and Bcl-extra large (Bcl-xL)] were also assessed. Paeonol treatment enhanced apoptosis of SKOV-3 and OVCAR-3 cells that were exposed to radiation. The expression of Bcl-2 and Bcl-xL were markedly upregulated in these cells. Treatment with paeonol concentrations of 50 and 100 µM caused a significant downregulation of VEGF, HIF-1α and PI3K/Akt pathway proteins. Paeonol effectively enhanced the sensitivity of ovarian cancer cells to radiation by significantly altering regulation of the proteins of the PI3K/Akt pathway, in addition to downregulating VEGF and HIF-1α.

Correlations of EGF G1380A, bFGF C754G and VEGF T460C polymorphisms with malignant melanoma susceptibility and prognosis: A case-control study

This case-control study aims to investigate the correlations of EGF G1380A, bFGF C754G and VEGF T460C polymorphisms with the susceptibility and prognosis of malignant melanoma. A total of 153 patients with multiple primary melanomas were collected as the case group and another 170 healthy individuals were selected as the control group. ELISA and PCR-RFLP were performed to test the serum level of VEGF and to analyze the genotype as well as allele frequencies of VEGF T460C, EGF G1380A, and bFGF C754G, respectively. The patients were assigned into complete remission (CR), partial remission (PR) and non-remission groups after treatment. HE and CD34 staining were conducted in tissue samples of CR and PR patients. Event-free survival (EFS) and overall survival (OS) were measured. AA genotype of EGF G1380A and GG genotype of bFGF C754G had higher frequency distribution in the case group than the control group. Patients with AA genotype of EGF G1380 and GG genotype of bFGF C754G had an elevated VEGF level in comparison to other genotypes. Patients with GA+GG genotypes of EGF G1380A and CG+CC genotypes of bFGF C754G had higher EFS and OS than those with AA genotype and those with GG genotype, respectively. According to the haplotype analysis, the case group had a notably higher frequency of TAG and CAG along with while lower frequency of TGG and CGC compared with the control group. Logistic regression analysis revealed that the polymorphisms of EGF G1380A and bFGF C754G as well as the haploid TAG increased the susceptibility of malignant melanoma. The results indicated that EGF G1380A and bFGF C754G gene polymorphisms were associated with the susceptibility and prognosis of malignant melanoma, and that the polymorphisms of EGF G1380A and bFGF C754G as well as the haploid TAG increased the susceptibility of malignant melanoma.

Tyrosine Kinase Receptor Expression in Canine Liposarcoma

The expression of tyrosine kinase receptors is attracting major interest in human and veterinary oncological pathology because of their role as targets for adjuvant therapies. Little is known about tyrosine kinase receptor (TKR) expression in canine liposarcoma (LP), a soft tissue sarcoma. The aim of this study was to evaluate the immunohistochemical expression of the TKRs fibroblast growth factor receptor 1 (FGFR1) and platelet-derived growth factor receptor–β (PDGFRβ); their ligands, fibroblast growth factor 2 (FGF2) and platelet-derived growth factor B (PDGFB); and c-kit in canine LP. Immunohistochemical labeling was categorized as high or low expression and compared with the mitotic count and MIB-1–based proliferation index. Fifty canine LPs were examined, classified, and graded. Fourteen cases were classified as well differentiated, 7 as myxoid, 25 as pleomorphic, and 4 as dedifferentiated. Seventeen cases were grade 1, 26 were grade 2, and 7 were grade 3. A high expression of FGF2, FGFR1, PDGFB, and PDGFRβ was identified in 62% (31/50), 68% (34/50), 81.6% (40/49), and 70.8% (34/48) of the cases, respectively. c-kit was expressed in 12.5% (6/48) of the cases. Mitotic count negatively correlated with FGF2 ( R = –0.41; P < .01), being lower in cases with high FGF2 expression, and positively correlated with PDGFRβ ( R = 0.33; P < .01), being higher in cases with high PDGFRβ expression. No other statistically significant correlations were identified. These results suggest that the PDGFRβ-mediated pathway may have a role in the progression of canine LP and may thus represent a promising target for adjuvant cancer therapies.

Paeonol enhances thrombus recanalization by inducing vascular endothelial growth factor 165 via ERK1/2 MAPK signaling pathway

Paeonol (2'-hydroxy-4'-methoxyacetophenone) is the major active compound of Mautan cortex and has been demonstrated to inhibit platelet aggregation in previous studies. The current study aimed to elucidate the underlying molecular mechanism of paeonol in recanalizing thrombi. The presence of indicators of prothrombotic state (PTS) in the serum of the model animals were determined by enzyme‑linked immunosorbent assay (ELISA) assay and the cytotoxicity of paeonol on human umbilical vein endothelial cell (HUVEC) cultures was estimated by 3‑(4,5 dimethylthiazol‑2‑yl)-2,5-diphenyltetrazolium bromide assay. The possible underlying signaling pathway involved in the interaction between paeonol and vascular endothelial growth factor 165 (VEGF165) was investigated using western blotting. The levels of 6‑keto‑prostaglandin F1α, fibronectin, and VEGF165 in serum were significantly upregulated by the treatment of paeonol while the levels of fibrinogen, D‑dimer, and thromboxane B2 were significantly downregulated (P<0.05). With increased paeonol concentration, the cell viability of HUVECs gradually decreased. The results of the western blot analysis demonstrated that paeonol increased the expression levels of phosphorylated‑extracellular signal‑regulated kinase (ERK1/2) and VEGF165 but had no marked effect on the expression level of ERK1/2. Paeonol has the potential to improve PTS and recanalize thrombi in animal models, which may be by the upregulation of VEGF165 via the ERK1/2 mitogen activated protein kinase signaling pathway. However, this positive effect depended on the concentration of paeonol used, an unsuitably high concentration of the compound exerted negative effects on the anti‑thrombosis signaling pathways.

Hyaluronan/RHAMM interactions in mesenchymal tumor pathogenesis: role of growth factors

Fibrosarcoma belongs to the sarcoma cancer group, which are spindle cell malignancies of mesenchymal origin, and owe their name to the predominant cell line that is present within the tumor. The extracellular matrix (ECM) is a complicated structure that surrounds and supports cells within tissues. Its main components are proteoglycans, collagens, glycoproteins, hyaluronan (HA), and several matrix-degrading enzymes. During cancer progression, significant changes can be observed in the structural and mechanical properties of ECM components. The ECM provides a physical scaffold to which tumor cells attach and migrate. Thus, it is required for key cellular events such as cell motility, adhesion, proliferation, invasion, and metastasis. Importantly, fibrosarcomas were shown to have a high content and turnover of ECM components including HA, proteoglycans, collagens, fibronectin, and laminin. In this review, we will focus on the HA component of fibrosarcoma ECM and critically discuss its role and involved mechanisms during fibrosarcoma pathogenesis.

Paeonol suppresses chondrosarcoma metastasis through up-regulation of miR-141 by modulating PKCδ and c-Src signaling pathway

Chondrosarcoma, a primary malignant bone cancer, has potential for local invasion and distant metastasis, especially to the lungs. Patients diagnosed with it show poor prognosis. Paeonol (2'-hydroxy-4'-methoxyacetophenone), the main active compound of traditional Chinese remedy Paeonia lactiflora Pallas, exhibits anti-inflammatory and anti-tumor activity; whether paeonol regulates metastatic chondrosarcoma is largely unknown. Here, we find paeonol do not increase apoptosis. By contrast, at non-cytotoxic concentrations, paeonol suppresses migration and invasion of chondrosarcoma cells. We also demonstrate paeonol enhancing miR-141 expression and miR-141 inhibitor reversing paeonol-inhibited cell motility; paeonol also reduces protein kinase C (PKC)d and c-Src kinase activity. Since paeonol inhibits migration and invasion of human chondrosarcoma via up-regulation of miR-141 via PKCd and c-Src pathways, it thus might be a novel anti-metastasis agent for treatment of metastatic chondrosarcoma.

Inflammatory stress and sarcomagenesis: a vicious interplay

Chronic inflammation represents one of the hallmarks of cancer, but its role in sarcomagenesis has long been overlooked. Sarcomas are a rare and heterogeneous group of tumors of mesenchymal origin accounting for less than 1 % of cancers in adults but 21 % of cancers in the pediatric population. Sarcomas are associated with bad prognosis, and their management requires a multidisciplinary team approach. Several lines of evidence indicate that inflammation has been implicated in sarcomagenesis leading to the activation of the key transcription factors HIF-1, NF- κB, and STAT-3 involved in a complex inflammatory network. In the past years, an increasing number of new targets have been identified in the treatment of sarcomas leading to the development of new drugs that aim to interrupt the vicious connection between inflammation and sarcomagenesis. This article makes a brief overview of preclinical and clinical evidence of the molecular pathways involved in the inflammatory stress response in sarcomagenesis and the most targeted therapies.

The role of inflammation in sarcoma

Sarcomas encompass a heterogenous group of tumors with diverse pathologically and clinically overlapping features. It is a rarely curable disease, and their management requires a multidisciplinary team approach. Chronic inflammation has emerged as one of the hallmarks of tumors including sarcomas. Classical inflammation-associated sarcomas comprise the inflammatory malignant fibrous histiocytoma and Kaposi sarcoma. The identification of specific chromosomal translocations and important intracellular signaling pathways such as Ras/Raf/MAPK, insulin-like growth factor, PI3K/AKT/mTOR, sonic hedgehog and Notch together with the increasing knowledge of angiogenesis has led to development of targeted therapies that aim to interrupt these pathways. Innovative agents like oncolytic viruses opened the way to design new therapeutic options with encouraging findings. Preclinical evidence also highlights the therapeutic potential of anti-inflammatory nutraceuticals as they can inhibit multiple pathways while being less toxic. This chapter gives an overview of actual therapeutic standards, newest evidence-based studies and exciting options for targeted therapies in sarcomas.

Paeonol induces apoptosis in human ovarian cancer cells

Paeonol is a broad-spectrum antitumor agent, which is widely used in the treatment of various tumors in Asia. However, the effect of paeonol on ovarian cancer remains unclear. The purpose of this study was to investigate the effect of paeonol on ovarian cancer cells and its possible mechanism. Results measured by MTT (methyl thiazoyltetrazolium) assay showed that cell viability was markedly reduced in a dosage-dependent manner, when treated with paeonol for 24 h. Flow cytometry and Hoechst staining results indicated that the rate of apoptosis in the paeonol pretreatment group was higher than the control group. After co-culture with paeonol, cleaved Caspase 3 protein levels increased while survivin protein levels decreased. In conclusion, our findings indicate that paeonol can induce apoptosis of ovarian cancer cells via activation of Caspase 3 and down-regulation of survivin, and therefore is potentially an effective chemotherapeutic agent for ovarian cancer.

Endoplasmic reticulum stress-induced resistance to doxorubicin is reversed by paeonol treatment in human hepatocellular carcinoma cells

Background

Endoplasmic reticulum stress (ER stress) is generally activated in solid tumors and results in tumor cell anti-apoptosis and drug resistance. Paeonol (Pae, 2-hydroxy-4-methoxyacetophenone), is a natural product extracted from the root of Paeonia Suffruticosa Andrew. Although Pae displays anti-neoplastic activity and increases the efficacy of chemotherapeutic drugs in various cell lines and in animal models, studies related to the effect of Pae on ER stress–induced resistance to chemotherapeutic agents in hepatocellular carcinoma (HCC) are poorly understood.

Methodology/Principal Findings

In this study, we investigated the effect of the endoplasmic reticulum (ER) stress response during resistance of human hepatocellular carcinoma cells to doxorubicin. Treatment with the ER stress-inducer tunicamycin (TM) before the addition of doxorubicin reduced the rate of apoptosis induced by doxorubicin. Interestingly, co-pretreatment with tunicamycin and Pae significantly increased apoptosis induced by doxorubicin. Furthermore, induction of ER stress resulted in increasing expression of COX-2 concomitant with inactivation of Akt and up-regulation of the pro-apoptotic transcription factor CHOP (GADD153) in HepG2 cells. These cellular changes in gene expression and Akt activation may be an important resistance mechanism against doxorubicin in hepatocellular carcinoma cells undergoing ER stress. However, co-pretreatment with tunicamycin and Pae decreased the expression of COX-2 and levels of activation of Akt as well as increasing the levels of CHOP in HCC cells.

Conclusions/Significance

Our results demonstrate that Pae reverses ER stress–induced resistance to doxorubicin in human hepatocellular carcinoma cells by targeting COX-2 mediated inactivation of PI3K/AKT/CHOP.

Effects of paeonol on intracellular calcium concentration and expression of RUNX3 in LoVo human colon cancer cells

Paeonol, a major phenolic component of the root bark of Paeonia moutan, is known to exhibit antitumor effects. However, the underlying mechanisms remain unknown. In the present study, the effects of paeonol on cell viability, intracellular calcium concentration and the expression of runt‑related transcription factor 3 (RUNX3) were analyzed in LoVo human colon cancer cells. Results revealed that paeonol markedly reduced LoVo cell viability in a time‑ and dose‑dependent manner. Flow cytometry assays demonstrated that paeonol blocked the cell cycle at the G1 to S transition and significantly induced apoptosis in LoVo cells. Intracellular calcium accumulation occurred following a 48 h treatment with paeonol. Furthermore, RUNX3 gene expression was increased in paeonol‑treated cells. These observations indicate that paeonol possesses antiproliferative properties and apoptosis‑inducing activity. One of the antitumor mechanisms of paeonol may be its apoptosis‑inducing activity through an increased intracellular calcium concentration and the upregulation of RUNX3 expression. Paeonol may be a promising antitumor agent for colon carcinoma treatment.

Vasculogenic mimicry of HT1080 tumour cells in vivo: critical role of HIF-1α-neuropilin-1 axis

HT1080 - a human fibrosarcoma-derived cell line – forms aggressive angiogenic tumours in immuno-compromised mice. In spite of its extensive use as a model of tumour angiogenesis, the molecular event(s) initiating the angiogenic program in these cells are not known. Since hypoxia stimulates tumour angiogenesis, we examined the hypoxia-induced events evoked in these cells. In contrast to cells grown under normoxic conditions, hypoxia-primed (1% O₂) HT1080 cells formed robust tubules on growth factor-reduced matrigel and formed significantly larger tumours in xenograft models in a chetomin-sensitive manner, indicating the role of HIF-1α-mediated transcription in these processes. Immuno-histochemical analyses of tumours formed by GFP-expressing HT1080 cells clearly showed that the tumour cells themselves expressed various angiogenic markers including Neuropilin-1 (NRP-1) and formed functional vessels containing red blood cells, thereby unambiguously demonstrating the vasculogenic mimicry of HT1080 cells in vivo. Experiments performed with the HT1080 cells stably transfected with plasmid constructs expressing shNRP-1 or full-length NRP-1 clearly established that the HIF1α-mediated up-regulation of NRP-1 played a deterministic role in the process. Hypoxia-exposure resulted in an up-regulation of c-Myc and OCT3/4 and a down-regulation of KLF4 mRNAs, suggesting their involvement in the tumour formation and angiogenesis. However, silencing of NRP-1 alone, though not affecting proliferation in culture, was sufficient to abrogate the tumour formation completely; clearly establishing that the hypoxia-mediated HIF-1α-dependent up-regulation of NRP-1 is a critical molecular event involved in the vasculogenic mimicry and tumor formation by HT1080 cells in vivo.

Formulation of liposomes gels of paeonol for transdermal drug delivery by Box-Behnken statistical design

The aim of this study was to design and optimize a transdermal liposomes gel formulation for paeonol (PAE). A three-factor, three-level Box-Behnken design was used to derive a second-order polynomial equation to construct three-dimensional (3-D) contour plots for prediction of responses. Independent variables studied were the DC-Chol concentration (X₁), molar ratio of lipid/drug (X₂), and the polymer concentration (X₃), and the levels of each factor were low, medium, and high. The dependent variables studied were the encapsulation efficiency (%EE) of PAE (Y₁), flux of PAE (Y₂), and viscosity of the gels (Y₃). Response surface plots were drawn and statistical validity of the polynomials was established to find the compositions of optimized formulation, which was evaluated using the Franz diffusion cell. The %EE of PAE increased proportionally with the molar ratio of lipid/drug, but decreased with polymer concentration, whereas the flux of PAE increased proportionally with polymer concentration and the DC-Chol concentration. The viscosity of gels increased with the polymer concentration. Gels showed a non-Fickian diffusion release mechanism for PAE, and the in vitro release profiles were fit for Higuchi's order model. The design demonstrated the role of the derived polynomial equation and 3-D contour plots in predicting the values of dependent variables for the preparation and optimization of gel formulation for transdermal drug release.

Emodin inhibits proinflammatory responses and inactivates histone deacetylase 1 in hypoxic rheumatoid synoviocytes

Chronic inflammation of rheumatoid arthritis (RA) is promoted by proinflammatory cytokines and closely linked to angiogenesis. In the present study, we investigated the anti-inflammatory effects of emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) isolated from the root of Rheum palmatum L. in interleukin 1 beta (IL-1β) and lipopolysaccharide (LPS)-stimulated RA synoviocytes under hypoxia. Emodin significantly inhibited IL-1β and LPS-stimulated proliferation of RA synoviocytes in a dose-dependent manner under hypoxic condition. Also, enzyme linked immunosorbent assay (ELISA) revealed that emodin significantly reduced the production of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α), IL-6 and IL-8], mediators [prostagladin E(2) (PGE(2)), matrix metalloproteinase (MMP)-1 and MMP-13] and vascular endothelial growth factor (VEGF) as an angiogenesis biomarker in IL-1β and LPS-treated synoviocytes under hypoxia. Consistently, emodin attenuated the expression of cyclooxygenase 2 (COX-2), VEGF, hypoxia inducible factor 1 alpha (HIF-1α), MMP-1 and MMP-13 at mRNA level in IL-1β and LPS-treated synoviocytes under hypoxia. Furthermore, emodin reduced histone deacetylase (HDAC) activity as well as suppressed the expression of HDAC1, but not HDAC2 in IL-1β and LPS-treated synoviocytes under hypoxia. Overall, these findings suggest that emodin inhibits proinflammatory cytokines and VEGF productions, and HDAC1 activity in hypoxic RA synoviocytes.

Penta-O-galloyl-β-D-glucose attenuates cisplatin-induced nephrotoxicity via reactive oxygen species reduction in renal epithelial cells and enhances antitumor activity in Caki-2 renal cancer cells

Cisplatin shows limited therapeutic efficacy due to serious side effects such as nephrotoxicity and hepatotoxicity. In the present study, we demonstrate that 1,2,3,4,6-penta-O-galloyl-β-d-glucose (PGG) has protective effects against cisplatin-induced cytotoxicity and apoptosis in normal human primary renal epithelial cells (HRCs) while showing synergistic effect against cisplatin-induced cell death in human Caki-2 renal cancer cells. PGG significantly blocked cisplatin-mediated cytotoxicity and reduced cisplatin-induced sub-G1 accumulation in HRCs. Consistently, PGG reduced the number of apoptotic cell populations by TdT-mediated dUTP nick end labeling (TUNEL) and Live/Dead assays in cisplatin-treated HRCs. Furthermore, PGG suppressed PARP cleavage and caspase-3 activation, cytochrome c release, up-regulation of bax and p53 in cisplatin-treated HRCs. Moreover, PGG attenuated reactive oxygen species (ROS) production mediated by cisplatin treatment, suggesting that PGG prevented cisplatin-induced apoptosis by inhibiting ROS generation in HRCs. Notably, PGG significantly enhanced cytotoxicity and PARP cleavage in cisplatin-treated Caki-2 renal cancer cells. Combination Index (CI) revealed synergism between PGG and cisplatin in Caki-2 cells. Taken together, our findings suggest the dual effects of PGG as a protective supplement against cisplatin-induced toxicity in normal renal cells and a combination chemotherapeutic drug with cisplatin in renal cancer cells.

Suppression of STAT3 and HIF-1 alpha mediates anti-angiogenic activity of betulinic acid in hypoxic PC-3 prostate cancer cells

BACKGROUND

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates various cellular processes such as cell survival, angiogenesis and proliferation. In the present study, we examined that betulinic acid (BA), a triterpene from the bark of white birch, had the inhibitory effects on hypoxia-mediated activation of STAT3 in androgen independent human prostate cancer PC-3 cells.

METHODOLOGY/PRINCIPAL FINDINGS

BA inhibited the protein expression and the transcriptional activities of hypoxia-inducible factor-1α (HIF-1α) under hypoxic condition. Consistently, BA blocked hypoxia-induced phosphorylation, DNA binding activity and nuclear accumulation of STAT3. In addition, BA significantly reduced cellular and secreted levels of vascular endothelial growth factor (VEGF), a critical angiogenic factor and a target gene of STAT3 induced under hypoxia. Furthermore, BA prevented in vitro capillary tube formation in human umbilical vein endothelial cells (HUVECs) maintained in conditioned medium of hypoxic PC-3 cells, implying anti-angiogenic activity of BA under hypoxic condition. Of note, chromatin immunoprecipitation (ChiP) assay revealed that BA inhibited binding of HIF-1α and STAT3 to VEGF promoter. Furthermore, silencing STAT3 using siRNA transfection effectively enhanced the reduced VEGF production induced by BA treatment under hypoxia.

CONCLUSIONS/SIGNIFICANCE

Taken together, our results suggest that BA has anti-angiogenic activity by disturbing the binding of HIF-1α and STAT3 to the VEGF promoter in hypoxic PC-3 cells.