Up-regulation of p21 and TNF-alpha is mediated in lycorine-induced death of HL-60 cells

Lycorine suppresses cell growth and invasion via down-regulation of NEDD4 ligase in bladder cancer

Recent studies have shown that lycorine, a natural alkaloid compound, plays its anti-cancer role in several human malignancies including bladder cancer. However, the molecular mechanism of lycorine-induced antitumor activity has not been sufficiently investigated. The E3 ubiquitin ligase neural precursor cell expressed developmentally downregulated protein 4 (NEDD4, also known as NEDD4-1) plays a crucial role in tumorigenesis and progression of human cancer. Therefore, depletion of NEDD4 could be a prospective therapeutic strategy for the treatment of cancer. In this study, we investigated whether lycorine restrains tumor by inhibiting the expression of NEDD4 in bladder cancer. We observed that lycorine blocked bladder cancer cell proliferation, colony formation, metastasis and invasion. Moreover, we found that overexpression of NEDD4 in bladder cancer cells significantly promoted cell proliferation and motility, whereas downregulating of the NEDD4 gene expression by lycorine or siRNA suppressed cell growth and movement. Notably, lycorine increased gemcitabine sensitivity in bladder cancer cells. Importantly, lycorine significantly reduced tumor growth, whereas overexpression of NEDD4 accelerated tumor growth and rescued lycorine-triggered tumor inhibition in xenograft mouse model. In conclusion, our study demonstrated that lycorine could exert its antineoplastic activity via suppressing NEDD4 pathway in vitro and in vivo. Therefore, inhibition of NEDD4 expression by lycorine might be a potential efficient strategy for bladder cancer.

Lycorine and organ protection: Review of its potential effects and molecular mechanisms

BACKGROUND

Multiorgan dysfunction, especially sepsis-related multiorgan damage, remains a major cause of high mortality in the late stages of infection and a great clinical challenge. In recent years, natural drugs have received widespread attention because of their low cost, wide sources, high efficacy, low toxicity, and limited side effects. Lycorine, a natural compound extracted from Amaryllidaceae, exhibits multiple pharmacological activities, including in the regulation of autophagy and the induction of cancer cell apoptosis, and has anti-inflammatory, antifungal, antiviral, antimalarial, and antitumor activities. However, studies on lycorine have mainly focused on its antitumor properties, and research on its use for organ protection, especially in sepsis-related organ injury, is relatively limited.

PURPOSE

To review and discuss the effects and mechanisms of lycorine in the treatment of multi-organ dysfunction, especially sepsis.

METHODS

Literature searches in electronic databases, such as Web of Science, Science Direct, PubMed, Google Scholar, and Scopus, were performed using 'Lycorine', 'Amaryllidaceae', 'Pharmacology', 'Pharmacokinetics', 'Anti-inflammation', 'Autophagy', 'Apoptosis', 'Anti-microbial and anti-parasitic', 'Antitumor', 'Organ protection', and 'Sepsis' as keywords, the correlated literature was extracted and conducted from the databases mentioned above.

RESULTS

By summarizing the progress made in existing research, we found that the general effects of lycorine involve the regulation of autophagy and the induction of cancer cell apoptosis, and anti-inflammatory, antifungal, antiviral, antimalarial, and antitumor effects; through these pathways, the compound can ameliorate organ damage. In addition, lycorine was found to have an important effect on organ damage in sepsis.

CONCLUSION

Lycorine is a promising natural organ protective agent. This review will provide a new theoretical basis for the treatment of organ protection, especially in sepsis.

Lycorine inhibits cell proliferation and induced oxidative stress-mediated apoptosis via regulation of the JAK/STAT3 signaling pathway in HT-3 cells

Human cervical cancer is the fourth most common carcinoma in women in the world. The JAK/STAT3 signaling pathways crucially regulate cell growth and apoptosis. It is a significant target signaling pathway for the development of novel antitumor medicine. This study intended to explore whether lycorine could prevent HT-3 proliferation and induce apoptosis by targeting the JAK/STAT3 signaling cascade. The HT-3 cells were treated with various lycorine dosages and we analyzed cell growth, lipid peroxidation, antioxidants, mitochondrial membrane potential (ΔΨm), DNA damage, apoptosis markers by different in vitro methodologies. Our results revealed that lycorine substantially reserved cell growth via decreased antioxidants, augmented reactive oxygen species (ROS) generation which leads to loss of ΔΨm, increased nuclear crumbling and chromatin condensation, thus resulting in representative increased apoptotic cell death. Furthermore, we analyzed that the molecular mechanical action of lycorine considerably repressed JAK1/STAT3 transactional activation and decrease its downstream molecules Bcl-2, and enhances the expressional activity of Bax, cytochrome c, caspase 3 and 9 in HT-3 cells. Finally, the fact that N-acetylcysteine inhibits lycorine-induced ROS-mediated apoptosis was confirmed in HT-3 cells. Thus, the results indicate that lycorine efficiently enhances apoptosis and inhibits HT-3 cell proliferation. These outcomes collectively proposed that lycorine could be a beneficial chemotherapeutic agent for treating and managing human cervical carcinoma.

Identification of molecular anti-metastasis mechanisms of lycorine in colorectal cancer by RNA-seq analysis

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Metastasis is the major cause of death in patients with CRC. Lycorine, the phenanthridine alkaloid most commonly found in spp of the Amaryllidaceae family, has shown promising anticancer activities with minor side effects. However, the effects and the detailed mechanism of lycorine against metastasis of CRC remains unclear.

STUDY DESIGN/METHODS

The purpose of this study was to investigate the effects of lycorine on CRC and characterize the molecular mechanisms observed in lycorine-treated CRC cells using RNA-sequencing. MTT assay, colony formation assay, acridine orange/ethidium bromide (AO/EB) staining and Annexin V-FITC/Propidium iodide (PI) staining were conducted to examine the effects of lycorine on cell proliferation and apoptosis in CRC cells. RNA sequencing, real-time PCR assays and western blot were performed. Migration and invasion abilities of lycorine-treated CRC cells were investigated by wound healing and transwell invasion assays. The mouse CRC lung metastasis model was established and was used to detect the effect of lycorine on CRC in vivo.

RESULTS

Our results demonstrated that lycorine inhibited the proliferation and colony formation of CRC cells in a concentration-dependent manner. AO/EB staining and Annexin V-FITC/PI staining showed that lycorine induced apoptosis in a concentration-dependent manner. Lycorine also reduced lung metastasis of CRC in vivo. Moreover, transcriptomic analysis suggested that lycorine regulated the expression of 3556 genes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway was implicated according to the differentially expressed genes (DEGs), and multiple pathways including those of mitogen-activated protein kinase (MAPK), relaxin, Ras, phosphatidylinositol 3‑kinase (PI3K)-protein kinase B (Akt) and Wnt/β-catenin were selected by functional enrichment analyses. Furthermore, based on transcriptomic analysis, we found that the tumor necrosis factor (TNF) pathway and endoplasmic reticulum stress were responsible for lycorine-induced apoptosis.

CONCLUSIONS

These results obtained in this study demonstrated that lycorine has the potential to suppress CRC in vitro and in vivo through the lycorine-regulated multiple signaling pathways.

Lycorine inhibits cell proliferation, migration and invasion, and primarily exerts in vitro cytostatic effects in human colorectal cancer via activating the ROS/p38 and AKT signaling pathways

Colorectal cancer (CRC) is a life‑threatening malignant tumor of the digestive tract. Diverse gene mutations and complicated alterations to the signaling pathways in CRC lead to heterogeneity in response to chemotherapy. Moreover, anticancer drugs for CRC chemotherapy are limited due to adverse events. Therefore, developing more effective, tolerable and safe drugs for the treatment of CRC is important. The present study aimed to investigate the effect of lycorine on human CRC cell proliferation, migration, invasion, apoptosis, cell cycle distribution, as well as the underlying molecular mechanism. The crystal violet staining and MTT assay results demonstrated that lycorine suppressed cell proliferation in a dose‑ and time‑dependent manner in the three CRC cell lines, HCT116, LoVo and SW480. Similarly, verified by performing wound healing and Transwell assays, lycorine significantly inhibited HCT116 and LoVo cell migration and invasion in vitro compared with the control group. In LoVo cells, the protein expression levels of matrix metallopeptidases, snail family transcriptional repressor 1, Vimentin and N‑cadherin were significantly downregulated, whereas the protein expression levels of E‑cadherin were significantly upregulated by lycorine treatment compared with the control group. The Hoechst 33258 staining and flow cytometry assay results indicated that lycorine mediated its cytostatic effect on CRC cells potentially via inducing cell cycle arrest, but not apoptosis. Compared with the control group, lycorine significantly induced HCT116 cell cycle arrest at the G2/M phase, but significantly induced LoVo cell cycle arrest at the S and G2/M phases. Furthermore, lycorine significantly downregulated the protein expression levels of cyclin D1 and cyclin E1, but significantly increased p21 and Smad4 protein expression levels in HCT116 and LoVo cells compared with the control group. The intracellular reactive oxygen species (ROS) measurement results also indicated that compared with the control group, lycorine significantly induced ROS accumulation, and increased phosphorylated‑p38 expression levels and AKT phosphorylation. Collectively, the present study suggested that lycorine might induce cell cycle arrest and exert cytostatic effects potentially via activating ROS/p38 and AKT signaling pathways in CRC cells.

Lycorine hydrochloride suppresses stress-induced premature cellular senescence by stabilizing the genome of human cells

Lycorine, a natural compound isolated from the traditional Chinese medicinal herb Lycoris radiata, exhibits multiple pharmacological effects, such as anti-inflammatory, antiviral, and anticancer effects. Accumulating evidence also indicates that lycorine might hold the potential to treat age-associated Alzheimer's disease. However, whether lycorine is involved in delaying the onset of cellular senescence and its underlying mechanisms has not been determined. Here, we demonstrate that the salt of lycorine, lycorine hydrochloride, significantly suppressed stress-induced premature cellular senescence (SIPS) by ~2-fold, as determined by senescence-associated beta-galactosidase (SA-β-gal) staining and the expression of p16 and p21. In addition, pretreating cells with lycorine hydrochloride significantly inhibited the expression of CXCL1 and IL1α, two factors of the senescence-associated secreted phenotype (SASP) in SIPS cells. Further experiments revealed that lycorine hydrochloride promoted both the homologous recombination (HR) and nonhomologous end joining (NHEJ) pathways of DNA double-strand break (DSB) repair. Mechanistic studies suggested that lycorine hydrochloride treatment promoted the transcription of SIRT1 and SIRT6, critical longevity genes positively regulating both HR and NHEJ repair pathways, thereby stimulating DSB repair and stabilizing genomes. Inhibiting SIRT1 enzymatic activity abrogated the protective effect of lycorine hydrochloride on delaying the onset of SIPS, repairing DSBs, and restoring genome integrity. In summary, our work indicates that lycorine hydrochloride might hold therapeutic potential for treating age-associated diseases or promoting healthy aging by stabilizing genomes.

Protein mass spectrometry reveals lycorine exerting anti-multiple-myeloma effect by acting on VDAC2 and causing mitochondrial abnormalities

OBJECTIVE

Two-dimensional electrophoresis (2-DE) and MALDI-TOF/TOF mass spectrometry were performed to compare the proteomic alterations of lycorine-treated and control cells to further investigate the anti-multiple myeloma (MM) mechanisms of lycorine.

RESULTS

Mass spectrometry results showed that after lycorine treatment of MM cells, 42% of the differentially expressed proteins had subcellular localization, mainly, on mitochondria. Voltage-dependent anion-selective channel protein 2 (VDAC2), the most abundant protein in the outer mitochondrial membrane, was up-regulated after treatment with lycorine and was subsequently verified by western blot analysis. Further studies on mitochondria found that lycorine was able to increase abnormal mitochondria and increase mitochondrial membrane potential.

CONCLUSIONS

Lycorine can achieve the effect of resisting multiple myeloma by acting on VDAC2 and causing mitochondrial abnormalities.

Natural Compound Library Screening Identifies New Molecules for the Treatment of Cardiac Fibrosis and Diastolic Dysfunction

BACKGROUND

Myocardial fibrosis is a hallmark of cardiac remodeling and functionally involved in heart failure development, a leading cause of deaths worldwide. Clinically, no therapeutic strategy is available that specifically attenuates maladaptive responses of cardiac fibroblasts, the effector cells of fibrosis in the heart. Therefore, our aim was to develop novel antifibrotic therapeutics based on naturally derived substance library screens for the treatment of cardiac fibrosis.

METHODS

Antifibrotic drug candidates were identified by functional screening of 480 chemically diverse natural compounds in primary human cardiac fibroblasts, subsequent validation, and mechanistic in vitro and in vivo studies. Hits were analyzed for dose-dependent inhibition of proliferation of human cardiac fibroblasts, modulation of apoptosis, and extracellular matrix expression. In vitro findings were confirmed in vivo with an angiotensin II-mediated murine model of cardiac fibrosis in both preventive and therapeutic settings, as well as in the Dahl salt-sensitive rat model. To investigate the mechanism underlying the antifibrotic potential of the lead compounds, treatment-dependent changes in the noncoding RNAome in primary human cardiac fibroblasts were analyzed by RNA deep sequencing.

RESULTS

High-throughput natural compound library screening identified 15 substances with antiproliferative effects in human cardiac fibroblasts. Using multiple in vitro fibrosis assays and stringent selection algorithms, we identified the steroid bufalin (from Chinese toad venom) and the alkaloid lycorine (from Amaryllidaceae species) to be effective antifibrotic molecules both in vitro and in vivo, leading to improvement in diastolic function in 2 hypertension-dependent rodent models of cardiac fibrosis. Administration at effective doses did not change plasma damage markers or the morphology of kidney and liver, providing the first toxicological safety data. Using next-generation sequencing, we identified the conserved microRNA 671-5p and downstream the antifibrotic selenoprotein P1 as common effectors of the antifibrotic compounds.

CONCLUSIONS

We identified the molecules bufalin and lycorine as drug candidates for therapeutic applications in cardiac fibrosis and diastolic dysfunction.

Lycorine: A prospective natural lead for anticancer drug discovery

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Outline of the anticancer properties and associated molecular mechanism mediated by lycorine.

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Comprehensive analysis of the structure activity relationship associated with anticancer activity of lycorine.

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Summary of the pharmacological aspects and implications for future directions with this compound.

Nature is the most abundant source for novel drug discovery. Lycorine is a natural alkaloid with immense therapeutic potential. Lycorine is active in a very low concentration and with high specificity against a number of cancers both in vivo and in vitro and against various drug-resistant cancer cells. This review summarized the therapeutic effect and the anticancer mechanisms of lycorine. At the same time, we have discussed the pharmacology and comparative structure-activity relationship for the anticancer activity of this compound. The researches outlined in this paper serve as a foundation to explain lycorine as an important lead compound for new generation anticancer drug design and provide the principle for the development of biological strategies to utilize lycorine in the treatment of cancers.

Lycorine inhibits the growth and metastasis of breast cancer through the blockage of STAT3 signaling pathway

Signal transducer and activator of transcription 3 (STAT3) is involved in the growth and metastasis of breast cancer, and represents a potential target for developing new anti-tumor drugs. The purpose of this study is to investigate whether Lycorine, a pyrrolo[de]phenanthridine ring-type alkaloid extracted from Amaryllidaceae genera, could inhibit breast cancer by targeting STAT3 signaling pathway. The human breast cancer cell lines were incubated with various concentrations of Lycorine, and cell proliferation, colony formation, cell cycle distribution, apoptosis, migration and invasion were assayed by several in vitro approaches. Results showed that Lycorine significantly suppressed cell proliferation, colony formation, migration and invasion, as well as induced cell apoptosis, but showed no apparent impact on cell cycle. In addition, the effect of Lycorine on tumor growth and metastasis in nude mouse models was investigated, and results showed that Lycorine significantly inhibited tumor growth and metastasis in vivo. Mechanistically, Lycorine significantly inhibited STAT3 phosphorylation and transcriptional activity through upregulating SHP-1 expression. Lycorine also downregulated the expressions of STAT3 target genes, including Mcl-1, Bcl-xL, MMP-2, MMP-9, which are involved in apoptosis and invasion of breast cancer. Taken together, these findings suggest that Lycorine may be a promising candidate for the prevention and treatment of human breast cancer.

Synergistic effects of the immune checkpoint inhibitor CTLA-4 combined with the growth inhibitor lycorine in a mouse model of renal cell carcinoma

Renal cell carcinoma (RCC) management has undergone a major transformation over the past decade; immune checkpoint inhibitors are currently undergoing clinical trials and show promising results. However, the effectiveness of immune checkpoint inhibitors in patients with metastatic RCC (mRCC) is still limited. Lycorine, an alkaloid extracted from plants of the Amaryllidaceae family, is touted as a potential anti-cancer drug because of its demonstrative growth inhibition capacity (induction of cell cycle arrest and inhibition of vasculogenic mimicry formation). Moreover, T cell checkpoint blockade therapy with antibodies targeting cytotoxic T-lymphocyte associated protein 4 (CTLA-4) has improved outcomes in cancer patients. However, the anti-tumor efficacy of combined lycorine and anti-CTLA-4 therapy remains unknown. Thus, we investigated a combination therapy of lycorine hydrochloride and anti-CTLA-4 using a murine RCC model. As a means of in vitro confirmation, we found that lycorine hydrochloride inhibited the viability of various RCC cell lines. Furthermore, luciferase-expressing Renca cells were implanted in the left kidney and the lung of BALB/c mice to develop a RCC metastatic mouse model. Lycorine hydrochloride and anti-CTLA-4 synergistically decreased tumor weight, lung metastasis, and luciferin-staining in tumor images. Importantly, the observed anti-tumor effects of this combination were dependent on significantly suppressing regulatory T cells while upregulating effector T cells; a decrease in regulatory T cells by 31.43% but an increase in effector T cells by 31.59% were observed in the combination group compared with those in the control group). We suggest that a combination of lycorine hydrochloride and anti-CTLA-4 is a viable therapeutic option for RCC patients.

Lycorine is a novel inhibitor of the growth and metastasis of hormone-refractory prostate cancer

Lycorine, a natural alkaloid extracted from the Amaryllidaceae plant family, has been reported to exhibit a wide range of physiological effects, including the potential effect against cancer. However, the anti-prostate cancer (PCa) efficacy of Lycorine remains unrevealed. In this context, we figured out Lycorine's anti-proliferative and anti-migratory properties for PCa treatment. Lycorine inhibited proliferation of various PCa cell lines, induced cell apoptosis and cell death. Here we showed that Lycorine decreased proliferation, migration, invasion, survival and EMT of prostate cancer cell lines. Subcutaneous and orthotopic xenotransplantations by ectopic implantation of the human hormone-refractory PC-3M-luc cells were used to confirm in vivo anticancer effects of Lycorine. Lycorine inhibited both growth and metastasis in multiple organs (liver, lung, kidney, spleen and bone) in vivo and improved mice survival. Lycorine prevented EGF-induced JAK/STAT signaling. Importantly, anti-cancer effects of Lycorine were dependent on STAT expression. We suggest that Lycorine is a potential therapeutic in prostate cancer.

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.

Lycorine induces programmed necrosis in the multiple myeloma cell line ARH-77

Lycorine, a natural alkaloid, has been widely reported to possess potential efficacy against cancer. However, the anti-multiple myeloma mechanism of lycorine is not fully understood. In this study, the results demonstrated that lycorine is effective against multiple myeloma cell line ARH-77 via inducing programmed necrosis. The mechanisms of lycorine on the multiple myeloma cell line ARH-77 are associated with G1 phase cell cycle arrest, mitochondrial dysfunction, reactive oxygen species (ROS) generation, ATP depletion, and DNA damage. Our results elucidate the new mechanism of lycorine against multiple myeloma.

ANKHD1 represses p21 (WAF1/CIP1) promoter and promotes multiple myeloma cell growth

ANKHD1 (Ankyrin repeat and KH domain-containing protein 1) is highly expressed and plays an important role in the proliferation and cell cycle progression of multiple myeloma (MM) cells. ANKHD1 downregulation modulates cell cycle gene expression and upregulates p21 irrespective of the TP53 mutational status of MM cell lines. The present study was aimed to investigate the role of ANKHD1 in MM in vitro clonogenicity and in vivo tumourigenicity, as well as the role of ANKHD1 in p21 transcriptional regulation. ANKHD1 silencing in MM cells resulted in significantly low no. of colonies formed and in slow migration as compared to control cells (p < 0.05). Furthermore, in xenograft MM mice models, tumour growth was visibly suppressed in mice injected with ANKHD1 silenced cells compared to the control group. There was a significant decrease in tumour volume (p = 0.006) as well as in weight (p = 0.02) in the group injected with silenced cells compared to those of the control group. Co-immunoprecipitation and chromatin immunoprecipitation (ChIP) assays confirmed the interaction between p21 and ANKHD1. Moreover, overexpression of ANKHD1 downregulated the activity of a p21 promoter in luciferase assays. Decrease in luciferase activity suggests a direct role of ANKHD1 in p21 transcriptional regulation. In addition confocal analysis after U266 cells were treated with Leptomycin B (LMB) for 24 h showed accumulation of ANKHD1 inside the nucleus as compared to untreated cells where ANKHD1 was found to be predominantly in cytoplasm. This suggests ANKHD1 might be shuttling between cytoplasm and nucleus. In conclusion, ANKHD1 promotes MM growth by repressing p21 a potent cell cycle regulator.

The circulating proteinase inhibitor α-1 antitrypsin regulates neutrophil degranulation and autoimmunity

Pathological inflammation and autoimmune disease frequently involve elevated neutrophil activity in the absence of infectious agents. Tumor necrosis factor-α (TNF-α) contributes to many of the problems associated with autoimmune diseases. We investigated the ability of serum α-1 antitrypsin (AAT) to control TNF-α biosynthesis and signaling in neutrophils and assessed whether AAT deficiency (AATD) is a TNF-α-related disease. In vitro studies demonstrate that serum AAT coordinates TNF-α intracellular signaling and neutrophil degranulation of tertiary and secondary granules via modulation of ligand-receptor interactions. AATD patients homozygous for the Z allele were characterized by increased activation of the TNF-α system, as demonstrated by increased membrane TNF-α levels and increased plasma concentrations of TNF receptor 1 and neutrophil-released secondary and tertiary granule proteins. The incidence of autoantibodies directed against degranulated lactoferrin and surface protein accessible to these antibodies was increased in ZZ-AATD, leading to an enhanced rate of neutrophil reactive oxygen species production. Treatment of ZZ-AATD individuals with AAT augmentation therapy resulted in decreased membrane TNF-α expression and plasma levels of granule antigenic proteins and immunoglobulin G class autoantibodies. These results provide a mechanism by which AAT augmentation therapy affects TNF-α signaling in the circulating neutrophil, indicating promising potential of this therapy for other TNF-α-related diseases.

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.

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.

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

Uncontrolled tumor cell proliferation and robust neovascularization are prominent features of aggressive ovarian cancers. Although great efforts in anti-ovarian cancer therapy have been made in the past 4 decades, the 5-year survival rates for ovarian cancer patients are still poor, and effective drugs to cure ovarian cancer patients are absent. In this study, we evaluated the anti-cancer effects of lycorine hydrochloride (LH), a novel anti-ovarian cancer agent, using the highly-invasive ovarian cancer cell line, Hey1B, as a model. Our data showed that LH effectively inhibited mitotic proliferation of Hey1B cells (half maximal inhibitory concentration=1.2μM) with very low toxicity, resulting in cell cycle arrest at the G2/M transition through enhanced expression of the cell cycle inhibitor p21 and marked down-regulation of cyclin D3 expression. Moreover, LH suppressed both the formation of capillary-like tubes by Hey1B cells cultured in vitro and the ovarian cancer cell-dominant neovascularization in vivo when administered to Hey1B-xenotransplanted mice. LH also suppressed the expression of several key angiogenic genes, including VE-cadherin, vascular endothelial growth factor, and Sema4D, and reduced Akt phosphorylation in Hey1B cells. These results suggest that LH selectively inhibits ovarian cancer cell proliferation and neovascularization and is a potential drug candidate for anti-ovarian cancer therapy.

ANKHD1 regulates cell cycle progression and proliferation in multiple myeloma cells

ANKHD1 is a multiple ankyrin repeat containing protein, highly expressed in cancers, such as acute leukemia. The present study was undertaken to determine the expression and functional significance of ANKHD1 in human Multiple Myeloma (MM). We found that ANKHD1 is highly expressed in MM patient cells and cell lines. In vitro, lentiviral mediated ANKHD1-shRNA inhibited proliferation and delayed S to G2M cell cycle progression in glucocorticoid resistant (U266) and sensitive (MM1S) MM cells. Further ANKHD1 silencing resulted in upregulation of cyclin dependent kinase inhibitor p21 irrespective of the p53 status of the MM cell lines. These data suggest that ANKHD1 might have a role in MM cell proliferation and cell cycle progression by regulating expression of p21.

In search of a cytostatic agent derived from the alkaloid lycorine: synthesis and growth inhibitory properties of lycorine derivatives

As a continuation of our studies aimed at the development of a new cytostatic agent derived from an Amaryllidaceae alkaloid lycorine, we synthesized 32 analogues of this natural product. This set of synthetic analogues included compounds incorporating selective derivatization of the C1 versus C2 hydroxyl groups, aromatized ring C, lactamized N6 nitrogen, dihydroxylated C3-C3a olefin functionality, transposed olefin from C3-C3a to C2-C3 or C3a-C4, and C1 long-chain fatty esters. All synthesized compounds were evaluated for antiproliferative activities in vitro in a panel of tumor cell lines including those exhibiting resistance to proapoptotic stimuli and representing solid cancers associated with dismal prognoses, such as melanoma, glioblastoma, and non-small-cell lung cancer. Most active analogues were not discriminatory between cancer cells displaying resistance or sensitivity to apoptosis, indicating that these compounds are thus able to overcome the intrinsic resistance of cancer cells to pro-apoptotic stimuli. 1,2-Di-O-allyllycorine was identified as a lycorine analogue, which is 100 times more potent against a U373 human glioblastoma model than the parent natural product. Furthermore, a number of synthetic analogues were identified as promising for the forthcoming in vivo studies.

Role of p21 and cyclin E in normal and secalonic acid D-inhibited proliferation of human embryonic palatal mesenchymal cells

Secalonic acid D (SAD), a cleft palate-inducing teratogen, has been shown to inhibit proliferation/cell cycle progression in association with alteration in the levels of cell cycle regulators, p21 and cyclin E. These studies were conducted to test the hypotheses that p21 and cyclin E play an important functional role in normal human embryonic palatal mesenchymal (HEPM) cell cycle and that their up- and down-regulation, respectively, by SAD is functionally significant to its cell cycle block. Using small interfering RNA (siRNA) to silence p21 gene and transient transfection to overexpress cyclin E in control & SAD-treated HEPM cells, cell proliferation was assessed using a combination of cell numbers, thymidine uptake, CDK2 activity and Ki-67 expression. The results showed that silencing of p21 gene, although increased cell proliferation/numbers and CDK2 activity in normal HEPM cells, failed to counteract SAD-induced anti-proliferative effect despite inducing partial recovery of CDK2 activity. Similar effects were apparent with cyclin E overexpression. It is concluded that p21 and cyclin E are important for normal HEPM cell proliferation. However, SAD-induced deregulation of either protein, singly, may not be sufficient to induce anti-proliferative effect. Involvement of other cell cycle proteins such as cyclin D1 or of multiple proteins in SAD-induced cell cycle block needs to be examined.