Lycorine hydrochloride selectively inhibits human ovarian cancer cell proliferation and tumor neovascularization with very low toxicity

The Biological Activity of Alkaloids from the Amaryllidaceae: From Cholinesterases Inhibition to Anticancer Activity

Modern research has shown that Amaryllidaceae alkaloids represent a rich reservoir of potential small chemical molecules exhibiting several medicinal properties through various mechanisms. Among the many Amaryllidaceae compounds, galanthamine has been given a great amount of attention due to the fact that it possesses potent acetylcholinesterase inhibitory activity. In spite of the amount of evidence indicating the potential usefulness of Amaryllidaceae alkaloids in therapy, research groups have focused their attention on the other alkaloids present in this plant family. New investigations have shed light on many aspects of the structure of Amaryllidaceae alkaloids and on their semisynthetic modification, function, and mechanisms underlying in vitro and in vivo activity. In addition, Amaryllidaceae alkaloids have frequently been identified as having promising cytotoxic properties against cancer cell lines. While follow-up studies have repeatedly shown that Amaryllidaceae alkaloids and their derivatives demonstrate antiproliferative, cytotoxic and apoptosis-inducing activity, the mechanisms remain unclear. This review addresses the most important Amaryllidaceae alkaloids with anticancer potential, particularly those that have been studied for the purpose of gaining a better understanding of the basis of the activity at the cellular and molecular level.

Lycorine protects cartilage through suppressing the expression of matrix metalloprotenases in rat chondrocytes and in a mouse osteoarthritis model

Extracellular matrix (ECM) degrading enzymes, including matrix metalloproteinases (MMPs), are critical for cartilage destruction in the progression of osteoarthritis (OA). Thus, identifying novel drugs, which suppress the synthesis of MMPs may facilitate the treatment of OA. The cytotoxicity of lycorine was determined using a CCK8 assay. The effects of lycorine on IL‑1β‑induced upregulation of MMPs and activation of mitogen‑activated protein kinase pathways were detected by western blot analysis and reverse transcription‑quantitative polymerase chain reaction. Hematoxylin and eosin staining and Safranin O staining were used to evaluate the effect of lycorine in a mouse anterior cruciate ligament transection model. In the present study, it was demonstrated for the first time, to the best of our knowledge, that lycorine (LY) suppressed interleukin‑1β (IL‑1β)‑induced synthesis of MMP‑3 and MMP‑13 in vitro. Molecular analysis revealed that LY abrogated the phosphorylation of c‑Jun N‑terminal kinase (JNK) and the activation of the nuclear factor (NF)‑κB signaling pathway caused by IL‑1β stimulation. In addition, in vivo experiments in a mouse anterior cruciate ligament transection model confirmed the protective role of LY on cartilage. Taken together, the data obtained in the present study demonstrated that LY suppressed the IL‑1β‑induced expression of MMP‑3 and MMP‑13 through inhibition of the JNK and NF‑κB pathways, suggesting that LY may be used as a potential drug for the treatment of OA.

Thrombomodulin reduces tumorigenic and metastatic potential of lung cancer cells by up-regulation of E-cadherin and down-regulation of N-cadherin expression

Thrombomodulin (TM) is an endothelial cell membrane protein and plays critical roles in anti-thrombosis, anti-inflammation, vascular endothelial protection, and is traditionally regarded as a "vascular protection god". In recent years, although TM has been reported to be down-regulated in a variety of malignant tumors including lung cancer, the role and mechanism of TM in lung cancer are enigmatic. In this study, we found that induction of TM overexpression by cholesterol-reducing drug atorvastatin significantly diminished the tumorigenic capability of the lung cancer cells. Moreover, we demonstrated that TM overexpression caused G0/G1 phase arrest and markedly reduced the colony forming capability of the cells. Furthermore, overexpression of TM inhibited cell migration and invasion. Consistently, depletion of TM promoted cell growth, reduced the cell population at the G0/G1 phase, and enhanced cell migratory ability. Mechanistic study revealed that TM up-regulated E-cadherin but down-regulated N-cadherin expression, resulting in reversal of epithelial-mesenchymal transition (EMT) in the lung cancer cells. Moreover, silencing TM expression led to decreased E-cadherin and increased N-cadherin. Taken together, our study suggests that TM functions as a tumor suppressive protein, providing a conceptual framework for inducing TM overexpression as a sensible strategy and approach for novel anti-lung cancer drug discovery.

Dehydroeffusol inhibits gastric cancer cell growth and tumorigenicity by selectively inducing tumor-suppressive endoplasmic reticulum stress and a moderate apoptosis

Gastric cancer is ranked as the third leading cause of cancer-related death in the world. Although extensive efforts have been made in recent decades to treat gastric cancer with various anticancer drugs, effective anti-gastric cancer therapeutics to cure the disease are still lacking in the clinics. Therefore, potent novel anti-gastric cancer drugs are greatly needed. In this study, we explored a novel anti-gastric cancer agent from a medicinal herb named Juncus effusus and found that the active component dehydroeffusol (DHE), a small molecular phenanthrene, effectively inhibited gastric cancer cell proliferation and tumorigenesis by inducing tumor suppressive endoplasmic reticulum (ER) stress and by triggering moderate apoptosis. Mechanistic studies revealed that DHE selectively activated the intracellular tumor suppressive stress response by promoting the overexpression of the key ER stress marker DNA damage-inducible transcript 3 (DDIT3), through upregulation of activating transcription factor 4 (ATF4). Concurrently, DHE suppressed the expression of the cell survival and ER stress marker glucose regulated protein of molecular mass 78 (GRP78) via downregulation of the transcription factor ATF6. In addition, DHE markedly activated the stress response signaling pathway MEKK4-MKK3/6-p38-DDIT3, but significantly inhibited ERK signaling. Our data suggest that DHE inhibits gastric cancer cell growth and tumorigenicity through selectively inducing a robust tumor suppressive ER stress response and a moderate apoptosis response. Therefore, DHE may provide a novel drug candidate for further development of potential anti-gastric cancer therapeutics.

In Vivo Cytotoxicity Studies of Amaryllidaceae Alkaloids

The plant family Amaryllidaceae is recognizable for its esthetic floral characteristics, its widespread usage in traditional medicine as well as its unique alkaloid principles. Few alkaloid-producing families rival the Amaryllidaceae in terms of the diversity of its structures as well as their wide applicability on the biological landscape. In particular, cytotoxic effects have come to be a dominant theme in the biological properties of Amaryllidaceae alkaloids. To this extent, a significant number of structures have been subjected to in vitro studies in numerous cell lines from which several targets have been identified as promising chemotherapeutics. By contrast, in vivo models of study involving these alkaloids have been carried out to a lesser extent and should prove crucial in the continued development of a clinical target such as pancratistatin. This survey examines the cytotoxic effects of Amaryllidaceae alkaloids in vivo and contrasts these against the corresponding in vitro effects.

Inhibition of 4NQO-Induced Oral Carcinogenesis by Dietary Oyster Shell Calcium

Oyster has gained much attention recently for its anticancer activity but it is unclear whether calcium, the major antitumor ingredient in oyster shell, is responsible for the anticarcinogenic role of the oyster. To address this issue, C57BL/6 mice were fed with the carcinogen 4-nitroquinoline-1-oxide (4NQO, 50 µg/mL) and normal diet or a diet containing oyster powder, oyster calcium, or calcium depleted oyster powder. The tongue tissue specimens isolated from these mice were histologically evaluated for hyperplasia, dysplasia, and papillary lesions, and then analyzed for proliferation and differentiation markers by immunohistochemistry. The results showed that mice on the diet containing oyster calcium significantly reduced rates of tumors in the tongue and proliferation and enhanced differentiation in the oral epithelium compared with the diet containing calcium depleted oyster powder. These results suggest that calcium in oyster plays a critical role in suppressing formation of oral squamous cell carcinoma and proliferation and promoting differentiation of the oral epithelium.

Lycorine suppresses RANKL-induced osteoclastogenesis in vitro and prevents ovariectomy-induced osteoporosis and titanium particle-induced osteolysis in vivo

Osteoclasts play an important role in diseases involving bone loss. In this study, we assessed the effect of a plant-derived natural alkaloid (lycorine, or LY) on osteoclastogenesis in vitro and in vivo. Our in vitro study showed that receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis could be inhibited by LY; this effect was due to inhibition of mitogen-activated protein kinase (MAPK) signalling via MAP kinase kinases (MKKs). The MAPK agonist anisomycin could partially rescue the inhibitory effect of LY. Furthermore, LY also played a protective role in both a murine ovariectomy (OVX)-induced osteoporosis model and a titanium particle-induced osteolysis model. These results confirmed that LY was effective in preventing osteoclast-related diseases in vivo. In conclusion, our results show that LY is effective in suppressing osteoclastogenesis and therefore could be used to treat OVX-induced osteoporosis and wear particle-induced osteolysis.

Advanced research on vasculogenic mimicry in cancer

Vasculogenic mimicry (VM) is a brand-new tumour vascular paradigm independent of angiogenesis that describes the specific capacity of aggressive cancer cells to form vessel-like networks that provide adequate blood supply for tumour growth. A variety of molecule mechanisms and signal pathways participate in VM induction. Additionally, cancer stem cell and epithelial-mesenchymal transitions are also shown to be implicated in VM formation. As a unique perfusion way, VM is associated with tumour invasion, metastasis and poor cancer patient prognosis. Due to VM's important effects on tumour progression, more VM-related strategies are being utilized for anticancer treatment. Here, with regard to the above aspects, we make a review of advanced research on VM in cancer.

Expression and clinical role of TCTP in epithelial ovarian cancer

The aim of this study is to investigate the potential role and prognostic significance of translationally controlled tumor protein (TCTP) in human epithelial ovarian cancer (EOC). Western blot was used to evaluate the expression of TCTP in eight fresh EOC tissues. Immunohistochemistry was performed on formalin-fixed paraffin-embedded sections of 119 cases of ovarian cancers. Kaplan-Meier method indicated the relation between TCTP and EOC patients' overall survival rate. Starvation and re-feeding was used to assess cell cycle. Knocking down of TCTP and CCK8 assay showed the role of TCTP in HO8910 cell cycle. We found that TCTP was overexpressed in carcinoma tissues compared with normal tissues. Immunohistochemistry revealed that TCTP expression was significantly associated with clinicopathologic variables. Kaplan-Meier analysis revealed that high TCTP expression was significantly related to poor prognosis of the patients. Starvation and re-feeding suggested TCTP played a critical role in HO8910 cell proliferation. Interference of TCTP and CCK8 assay showed that the TCTP-siRNA treated HO8910 cells grew more slowly than the control group. CCK-8 assays and terminal-deoxynucleoitidyl transferase mediated nick end labeling assays were also performed to demonstrate the cisplatin could inhibit the survival of HO8910 cells and promote their apoptosis. All the experiments we have done showed that TCTP could promote the progression of EOC and reduce the sensitiveness of HO8910 cells to cisplatin.

Biological and pharmacological activities of amaryllidaceae alkaloids

This review discusses the recent developments on biological and pharmacological activities of amaryllidaceae alkaloids with IC₅₀or EC₅₀values since 2005, supporting the potential therapeutic possibilities for the use of these compounds.

Mechanistic Insights to the Cytotoxicity of Amaryllidaceae Alkaloids

With over 500 individual compounds, the Amaryllidaceae alkaloids represent a large and structurally diverse group of phytochemicals. Coupled to this structural diversity is the significant array of biological properties manifested by many of its members, of which their relevance in motor neuron disease and cancer chemotherapy has attracted considerable attention. To this extent, galanthamine has evolved into a successful commercial drug for Alzheimer's disease since its approval by the FDA in 2001. Concurrently, there have been several positive indicators for the emergence of an anticancer drug from the Amaryllidaceae due to the potency of several of its representatives as cell line specific antiproliferative agents. In this regard, the phenanthridones such as pancratistatin and narciclasine have offered most promise since their advancement into clinical trials, following which there has been renewed interest in the cytotoxic properties of these alkaloids. Given this background, this review seeks to highlight the various mechanisms which have been invoked to corroborate the cytotoxic effects of Amaryllidaceae alkaloids.

HIF-1α induces VE-cadherin expression and modulates vasculogenic mimicry in esophageal carcinoma cells

AIM: To investigate whether hypoxia inducible factor (HIF)-1α modulates vasculogenic mimicry (VM) by upregulating VE-cadherin expression in esophageal squamous cell carcinoma (ESCC).

METHODS: Esophageal squamous cancer cell lines Eca109 and TE13 were transfected with plasmids harboring small interfering RNAs targeting HIF-1α or VE-cadherin. The proliferation and invasion of esophageal carcinoma cells were detected by MTT and Transwell migration assays. The formation of tubular networks of cells was analyzed by 3D culture in vitro. BALB/c nude mice were used to observe xenograft tumor formation. The relationship between the expression of HIF-1α and VE-cadherin, ephrinA2 (EphA2) and laminin5γ2 (LN5γ2) was measured by Western blot and real-time polymerase chain reaction.

RESULTS: Knockdown of HIF-1α inhibited cell proliferation (32.3% ± 6.1% for Eca109 cells and 38.6% ± 6.8% for TE13 cells, P < 0.05). Both Eca109 and TE13 cells formed typical tubular networks. The number of tubular networks markedly decreased when HIF-1α or VE-cadherin was knocked down. Expression of VE-cadherin, EphA2 and LN5γ2 was dramatically inhibited, but the expression of matrix metalloproteinase 2 had no obvious change in HIF-1α-silenced cells. Knockdown of VE-cadherin significantly decreased expression of both EphA2 and LN5γ2 (P < 0.05), while HIF-1α expression was unchanged. The time for xenograft tumor formation was 6 ± 1.2 d for Eca109 cells and Eca109 cells transfected with HIF-1α Neo control short hairpin RNA (shRNA) vector, and 8.4 ± 2.1 d for Eca109 cells transfected with an shRNA against HIF-1α. Knockdown of HIF-1α inhibited vasculogenic mimicry (VM) and tumorigenicity in vivo.

CONCLUSION: HIF-1α may modulate VM in ESCC by regulating VE-cadherin expression, which affects VM formation through EphA2 and LN5γ2.

Rapid and sensitive HPLC-MS/MS method for quantitative determination of lycorine from the plasma of rats

A simple, rapid and sensitive high-performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed and validated for determining lycorine in rat plasma. Plasma samples were prepared by a simple protein precipitation with methanol containing dextrorphan as internal standard. The chromatographic separation was performed on a Kromasil 60-5CN column (3 μm, 2.1 mm × 150 mm) with the mobile phase of methanol/water (containing 0.1% formic acid) (40:60, v/v) at a flow rate of 0.2 mL/min, the total analytical runtime was 5 min. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with Electronic Spray Ion by selected reaction monitoring (SRM) of the transitions at m/z 288.1→147.1 for lycorine and m/z 258.1→157.2 for dextrorphan, respectively. The calibration curve was linear over the range of 1-1000 ng/mL with the lower limit of quantification of 1 ng/mL for lycorine. The intra- and inter-day precision (R.S.D.%) were less than 8.5% and accuracy (R.E.%) was within ±7.0%. Lycorine was sufficiently stable under all relevant analytical conditions. This method was successfully applied to the pharmacokinetic study of lycorine in rats after intraperitoneal administration with different doses of 5, 10 and 20 mg/kg.

Cytotoxicity Studies of Lycorine Alkaloids of the Amaryllidaceae

The plant family Amaryllidaceae is renowned for its unique alkaloid constituents which possess a significant array of structural diversity. Several of these alkaloids are known for their interesting biological properties, of which galanthamine and pancratistatin have acquired a privileged status due to their relevance in the pharmaceutical arena. In particular, galanthamine represents the first prescription drug emanating from the Amaryllidaceae after its approval by the FDA in 2001 for the treatment of Alzheimer's disease. Following on this commercial success there have been sustained projections for the emergence of an anticancer agent related to pancratistatin due to the potency, selectivity, low toxicity and high tolerability typifying targets of this series of alkaloids. The lycorine series of alkaloids have also garnered widespread interest as cytotoxic agents and were amongst the earliest of the Amaryllidaceae constituents to exhibit such activity. To date over 100 of such naturally-occurring or synthetically-derived alkaloids have been screened for cytotoxic effects against a number of cancer cell lines. This survey examines the cytotoxic properties of lycorine alkaloids, highlights the outcomes of structure-activity relationship orientated studies and affords plausible insights to the mechanistic rationale behind these effects.

Unraveling the novel anti-osteosarcoma function of coptisine and its mechanisms

Uncontrolled cell proliferation and robust angiogenesis play critical roles in osteosarcoma growth and metastasis. In this study we explored novel agents derived from traditional Chinese medicinal herbs that potently inhibit osteosarcoma growth and metastasis. Coptisine, an active component of the herb Coptidis rhizoma, markedly inhibited aggressive osteosarcoma cell proliferation. Coptisine induced cell cycle arrest at the G0/G1 phase through downregulation of CDK4 and cyclin D1 expression and effectively suppressed tumor growth in a xenografted mouse model. Coptisine significantly impeded osteosarcoma cell migration, invasion, and capillary-like network formation by decreasing the expression of VE-cadherin and integrin ß3, and diminishing STAT3 phosphorylation. Coptisine significantly elevated blood erythrocyte and hemoglobin levels while still remaining within the normal range. It also moderately increased white blood cell and platelet counts. These data suggest that coptisine exerts a strong anti-osteosarcoma effect with very low toxicity and is a potential anti-osteosarcoma drug candidate.

Novel lycorine derivatives as anticancer agents: synthesis and in vitro biological evaluation

Lycorine, which is the most abundant alkaloid isolated from the Amaryllidaceae family of plants, reportedly exhibits promising anticancer activities. Herein, a series of novel lycorine derivatives were synthesized and evaluated for their in vitro inhibitory activities against seven different cancer cell lines, including A549, HCT116, SK-OV-3, NCI-H460, K562, MCF-7 and HL-60. The results indicated that compounds bearing diverse amine substituents at the C-2 position demonstrated good anticancer activities. The selectivity towards different cancer cell lines of the synthesized derivatives is discussed.

C1,C2-ether derivatives of the Amaryllidaceae alkaloid lycorine: retention of activity of highly lipophilic analogues against cancer cells

As a continuation of the studies aimed at the development of new anticancer agents derived from the Amaryllidaceae alkaloid lycorine, 35 C1,C2-ether analogues of this natural product were synthesized. The compounds were evaluated for antiproliferative activities in vitro in a panel of tumor cell lines with varied levels of apoptosis resistance. A strong correlation between the compound lipophilicity and anticancer activity was observed, indicating that cell permeability properties must be an important determinant in the design of lycorine-based anticancer agents. A theoretical docking model, consistent with the experimental observations, is presented.

Tumour vasculogenic mimicry is associated with poor prognosis of human cancer patients: a systemic review and meta-analysis

BACKGROUND

Vasculogenic mimicry (VM) has been reported in various malignant tumours and is known to play an important role in cancer progression and metastasis. However, the impact of VM on the overall survival of human cancer patients remains controversial. The goal of this study was to evaluate whether VM is associated with 5-year survival of human cancer patients.

METHODS

Twenty-two eligible clinical studies with data on both tumour cell-dominant VM and the 5-year survival of 3062 patients involved in 15 types of cancers were pooled in the meta-analysis.

RESULTS

The 5-year overall survival of VM-positive and -negative cancer patients was 31% and 56%, respectively. The relative risk (RR) of the 5-year survival of VM-positive patients was significantly higher than that of VM-negative cases (RR=1.531; 95% confidence interval (CI): 1.357-1.726; P<0.001). Notably, metastatic melanoma patients demonstrated a higher VM rate (45.3%) than patients with primary melanoma (23.1%) and showed worse 5-year survival, suggesting that VM contributes to tumour metastasis and poor prognosis in cancer patients. Subgroup analysis indicated that a poor 5-year survival was significantly associated with eight types of VM-positive malignant tumours, such as lung, colon, liver cancers, sarcomas and melanoma; but was not associated with the seven other types of cancers, such as prostate cancer. Heterogeneity and publication biases were found among the 22 studies, mainly due to the divergent characteristics of cancers and extremely low survival rate in six types of malignant tumours.

CONCLUSION

VM-positive cancer patients show a poor 5-year overall survival compared with VM-negative malignant tumour cases, particularly in metastatic cancer.

Multiple biological functions and pharmacological effects of lycorine

Lycorine is the major active component from the amaryllidaceae family plant Lycoris radiate, a represent traditional Chinese medicinal herb, and is one of the typical alkaloids with pyrrolophenanthridine nucleus core. Lycorine has drawn great interest in medicinal field due to its divergent chemical structures and multiple biological functions, as well as pharmacological effects on various diseases. Accumulated evidence shows that lycorine not only possesses strong pharmacological effects on many diseases, including anti-leukemia, anti-tumor, anti-angiogenesis, anti-virus, anti-bacteria, anti-inflammation, and antimalaria, but also exerts many other biological functions, such as inhibition of acetylcholinesterase and topoisomerase, suppression of ascorbic acid biosynthesis, and control of circadian period length. Notably, lycorine exhibits its numerous pharmacological effects on various diseases with very low toxicity and mild side effects. The divergent chemical structures, multiple biological functions, and very low toxicity of lycorine imply that the agent is a potential drug candidate that warrants for further preclinical and clinic investigation.

Tumor cell-mediated neovascularization and lymphangiogenesis contrive tumor progression and cancer metastasis

Robust neovascularization and lymphangiogenesis have been found in a variety of aggressive and metastatic tumors. Endothelial sprouting angiogenesis is generally considered to be the major mechanism by which new vasculature forms in tumors. However, increasing evidence shows that tumor vasculature is not solely composed of endothelial cells (ECs). Some tumor cells acquire processes similar to embryonic vasculogenesis and produce new vasculature through vasculogenic mimicry, trans-differentiation of tumor cells into tumor ECs, and tumor cell-EC vascular co-option. In addition, tumor cells secrete various vasculogenic factors that induce sprouting angiogenesis and lymphangiogenesis. Vasculogenic tumor cells actively participate in the formation of vascular cancer stem cell niche and a premetastatic niche. Therefore, tumor cell-mediated neovascularization and lymphangiogenesis are closely associated with tumor progression, cancer metastasis, and poor prognosis. Vasculogenic tumor cells have emerged as key players in tumor neovascularization and lymphangiogenesis and play pivotal roles in tumor progression and cancer metastasis. However, the mechanisms underlying tumor cell-mediated vascularity as they relate to tumor progression and cancer metastasis remain unclear. Increasing data have shown that various intrinsic and extrinsic factors activate oncogenes and vasculogenic genes, enhance vasculogenic signaling pathways, and trigger tumor neovascularization and lymphangiogenesis. Collectively, tumor cells are the instigators of neovascularization. Therefore, targeting vasculogenic tumor cells, genes, and signaling pathways will open new avenues for anti-tumor vasculogenic and metastatic drug discovery. Dual targeting of endothelial sprouting angiogenesis and tumor cell-mediated neovascularization and lymphangiogenesis may overcome current clinical problems with anti-angiogenic therapy, resulting in significantly improved anti-angiogenesis and anti-cancer therapies.