Proteomic screening of anaerobically regulated promoters from Salmonella and its antitumor applications

Genetic engineering of Salmonella spp. for novel vaccine strategies and therapeutics

Salmonella enterica is a diverse species that infects both humans and animals. S. enterica subspecies enterica consists of more than 1,500 serovars. Unlike typhoidal Salmonella serovars which are human host-restricted, non-typhoidal Salmonella (NTS) serovars are associated with foodborne illnesses worldwide and are transmitted via the food chain. Additionally, NTS serovars can cause disease in livestock animals causing significant economic losses. Salmonella is a well-studied model organism that is easy to manipulate and evaluate in animal models of infection. Advances in genetic engineering approaches in recent years have led to the development of Salmonella vaccines for both humans and animals. In this review, we focus on current progress of recombinant live-attenuated Salmonella vaccines, their use as a source of antigens for parenteral vaccines, their use as live-vector vaccines to deliver foreign antigens, and their use as therapeutic cancer vaccines in humans. We also describe development of live-attenuated Salmonella vaccines and live-vector vaccines for use in animals.

Bacterially mediated drug delivery and therapeutics: Strategies and advancements

It was already clinically apparent 150 years ago that bacterial therapy could alleviate diseases. Recently, a burgeoning number of researchers have been using bacterial regimens filled with microbial therapeutic leads to diagnose and treat a wide range of disorders and diseases, including cancers, inflammatory diseases, metabolic disorders and viral infections. Some bacteria that were designed to have low toxicity and high efficiency in drug delivery have been used to treat diseases successfully, especially in tumor therapy in animal models or clinical trials, thanks to the progress of genetic engineering and synthetic bioengineering. Therefore, genetically engineered bacteria can serve as efficient drug delivery vehicles, carrying nucleic acids or genetic circuits that encode and regulate therapeutic payloads. In this review, we summarize the development and applications of this approach. Strategies for genetically modifying strains are described in detail, along with their objectives. We also describe some controlled strategies for drug delivery and release using these modified strains as carriers. Furthermore, we discuss treatment methods for various types of diseases using engineered bacteria. Tumors are discussed as the most representative example, and other diseases are also briefly described. Finally, we discuss the challenges and prospects of drug delivery systems based on these bacteria.

Macrophage-mediated tumor-targeted delivery of engineered Salmonella typhimurium VNP20009 in anti-PD1 therapy against melanoma

Bacterial antitumor therapy has great application potential given its unique characteristics, including genetic manipulation, tumor targeting specificity and immune system modulation. However, the nonnegligible side effects and limited efficacy of clinical treatment limit their biomedical applications. Engineered bacteria for therapeutic applications ideally need to avoid their accumulation in normal organs and possess potent antitumor activity. Here, we show that macrophage-mediated tumor-targeted delivery of Salmonella typhimurium VNP20009 can effectively reduce the toxicity caused by administrating VNP20009 alone in a melanoma mouse model. This benefits from tumor-induced chemotaxis for macrophages combined with their slow release of loaded strains. Inspired by changes in the tumor microenvironment, including a decrease in intratumoral dysfunctional CD8⁺ T cells and an increase in PDL1 on the tumor cell surface, macrophages were loaded with the engineered strain VNP-PD1nb, which can express and secrete anti-PD1 nanoantibodies after they are released from macrophages. This novel triple-combined immunotherapy significantly inhibited melanoma tumors by reactivating the tumor microenvironment by increasing immune cell infiltration, inhibiting tumor cell proliferation, remodeling TAMs to an M1-like phenotype and prominently activating CD8⁺ T cells. These data suggest that novel combination immunotherapy is expected to be a breakthrough relative to single immunotherapy.

Use of Salmonella Bacteria in Cancer Therapy: Direct, Drug Delivery and Combination Approaches

Over the years, conventional cancer treatments, such as chemotherapy with only a limited specificity for tumors, have undergone significant improvement. Moreover, newer therapies such as immunotherapy have undergone a revolution to stimulate the innate as well as adaptive immune responses against the tumor. However, it has been found that tumors can be selectively colonized by certain bacteria, where they can proliferate, and exert direct oncolytic effects as well as stimulating the immune system. Bacterial-mediated cancer therapy (BMCT) is now one example of a hot topic in the antitumor field. Salmonella typhimurium is a Gram-negative species that generally causes self-limiting gastroenteritis in humans. This species has been designed and engineered in order to be used in cancer-targeted therapeutics. S. typhimurium can be used in combination with other treatments such as chemotherapy or radiotherapy for synergistic modification of the tumor microenvironment. Considerable benefits have been shown by using engineered attenuated strains for the diagnosis and treatment of tumors. Some of these treatment approaches have received FDA approval for early-phase clinical trials. This review summarizes the use of Salmonella bacteria for cancer therapy, which could pave the way towards routine clinical application. The benefits of this therapy include an automatic self-targeting ability, and the possibility of genetic manipulation to produce newly engineered attenuated strains. Nevertheless, Salmonella-mediated anticancer therapy has not yet been clinically established, and requires more research before its use in cancer treatment.

Modulation of Salmonella Tumor-Colonization and Intratumoral Anti-angiogenesis by Triptolide and Its Mechanism

The weakened tumour colonization of attenuated Salmonella has severely hampered its clinical development. In this study, we investigated whether an anti-inflammation and antiangiogenesis compound triptolide could improve the efficacy of VNP20009, a highly attenuated Salmonella strain, against mice melanoma. By comparing the effects of conventional VNP20009 monotherapy and a combination therapy that uses both triptolide and VNP20009, we found that triptolide significantly improved the tumour colonization of VNP20009 by reducing the number of infiltrated neutrophils in the melanoma, which led to a larger necrotic area in the melanoma. Moreover, the combination therapy suppressed tumour angiogenesis by reducing the expression of VEGF in a synergistic manner, retarding the growth of the melanoma. Our study revealed that triptolide could significantly enhance the antitumour effect of VNP20009 by modulating tumour angiogenesis and the host immune response, providing a new understanding of the strategy to improve Salmonella-mediated tumour therapy.

Angiogenic inhibitors delivered by the type III secretion system of tumor-targeting Salmonella typhimurium safely shrink tumors in mice

Despite of a growing number of bacterial species that apparently exhibit intrinsic tumor-targeting properties, no bacterium is able to inhibit tumor growth completely in the immunocompetent hosts, due to its poor dissemination inside the tumors. Oxygen and inflammatory reaction form two barriers and restrain the spread of the bacteria inside the tumors. Here, we engineered a Salmonella typhimurium strain named ST8 which is safe and has limited ability to spread beyond the anaerobic regions of tumors. When injected systemically to tumor-bearing immunocompetent mice, ST8 accumulated in tumors at levels at least 100-fold greater than parental obligate anaerobic strain ST4. ST8/pSEndo harboring therapeutic plasmids encoding Endostatin fused with a secreted protein SopA could target vasculature at the tumor periphery, can stably maintain and safely deliver a therapeutic vector, release angiogenic inhibitors through a type III secretion system (T3SS) to interfere with the pro-angiogenic action of growth factors in tumors. Mice with murine CT26 colon cancer that had been injected with ST8/pSEndo showed efficient tumor suppression by inducing more severe necrosis and inhibiting blooding vessel density within tumors. Our findings provide a therapeutic platform for indirectly acting therapeutic strategies such as anti-angiogenesis and immune therapy.

Tumor-targeted delivery of a C-terminally truncated FADD (N-FADD) significantly suppresses the B16F10 melanoma via enhancing apoptosis

Fas-associated protein with death domain (FADD), a pivotal adaptor protein transmitting apoptotic signals, is indispensable for the induction of extrinsic apoptosis. However, overexpression of FADD can form large, filamentous aggregates, termed death effector filaments (DEFs) by self-association and initiate apoptosis independent of receptor cross-linking. A mutant of FADD, which is truncated of the C-terminal tail (m-FADD, 182–205 aa) named N-FADD (m-FADD, 1–181 aa), can dramatically up-regulate the strength of FADD self-association and increase apoptosis. In this study, it was found that over-expression of FADD or N-FADD caused apoptosis of B16F10 cells in vitro, even more, N-FADD showed a more potent apoptotic effect than FADD. Meanwhile, Attenuated Salmonella Typhimurium strain VNP20009 was engineered to express FADD or N-FADD under the control of a hypoxia-induced NirB promoter and each named VNP-pN-FADD and VNP-pN-N-FADD. The results showed both VNP-pN-FADD and VNP-pN-N-FADD delayed tumor growth in B16F10 mice model, while VNP-pN-N-FADD suppressed melanoma growth more significantly than VNP-pN-FADD. Additionally, VNP-pN-FADD and VNP-pN-N-FADD induced apoptosis of tumor cells by activating caspase-dependent apoptotic pathway. Our results show that N-FADD is a more potent apoptotic inducer and VNP20009-mediated targeted expression of N-FADD provides a possible cancer gene therapeutic approach for the treatment of melanoma.

The microtubule-associated protein PRC1 promotes early recurrence of hepatocellular carcinoma in association with the Wnt/β-catenin signalling pathway

OBJECTIVES

Hepatocellular carcinoma (HCC) is the second leading cause of cancer mortality worldwide. Alterations in microtubule-associated proteins (MAPs) have been observed in HCC. However, the mechanisms underlying these alterations remain poorly understood. Our aim was to study the roles of the MAP protein regulator of cytokinesis 1 (PRC1) in hepatocarcinogenesis and early HCC recurrence.

DESIGN

PRC1 expression in HCC samples was evaluated by microarray, immunoblotting and immunohistochemistry analysis. Molecular and cellular techniques including siRNA-mediated and lentiviral vector-mediated knockdown were used to elucidate the functions and mechanisms of PRC1.

RESULTS

PRC1 expression was associated with early HCC recurrence and poor patient outcome. In HCC, PRC1 exerted an oncogenic effect by promoting cancer proliferation, stemness, metastasis and tumourigenesis. We further demonstrated that the expression and distribution of PRC1 is dynamically regulated by Wnt3a signalling. PRC1 knockdown impaired transcription factor (TCF) transcriptional activity, decreased Wnt target expression and reduced nuclear β-catenin levels. Mechanistically, PRC1 interacts with the β-catenin destruction complex, regulates Wnt3a-induced membrane sequestration of this destruction complex, inhibits adenomatous polyposis coli (APC) stability and promotes β-catenin release from the APC complex. In vivo, high PRC1 expression correlated with nuclear β-catenin and Wnt target expression. PRC1 acted as a master regulator of a set of 48 previously identified Wnt-regulated recurrence-associated genes (WRRAGs) in HCC. Thus, PRC1 controlled the expression and function of WRRAGs such as FANCI, SPC25, KIF11 and KIF23 via Wnt signalling.

CONCLUSIONS

We identified PRC1 as a novel Wnt target that functions in a positive feedback loop that reinforces Wnt signalling to promote early HCC recurrence.

Proteomic Findings in Melanoma

Although the emergence of proteomics as an independent branch of science is fairly recent, within a short period of time it has contributed substantially in various disciplines. The tool of mass spectrometry has become indispensable in the analysis of complex biological samples. Clinical applications of proteomics include detection of predictive and diagnostic markers, understanding mechanism of action of drugs as well as resistance mechanisms against them and assessment of therapeutic efficacy and toxicity of drugs in patients. Here, we have summarized the major contributions of proteomics towards the study of melanoma, which is a deadly variety of skin cancer with a high mortality rate.

Suppression of pancreatic ductal adenocarcinoma growth by intratumoral delivery of attenuated Salmonella typhimurium using a dual fluorescent live tracking system

Pancreatic ductal adenocarcinoma (PDAC) has the poorest prognosis among all malignancies and is resistant to almost all current therapies. Attenuated Salmonella typhimurium strain VNP20009 has been deployed as powerful anticancer agent in a variety of animal cancer models, and previous phase 1 clinical trials have proven its safety profiles. However, thus far, little is known about its effect on PDAC. Here, we established CFPAC-1 cell lines expressing an mKate2 protein and thus emitting far-red fluorescence in the subsequent xenograft implant. VNP20009 strain was further engineered to carry a luciferase cDNA, which catalyzes the light-emitting reaction to allow the observation of salmonella distribution and accumulation within tumor with live imaging. Using such VNP20009 strain and intratumoral delivery, we could reduce the growth of pancreatic cancer by inducing apoptosis and severe necrosis in a dosage dependent manner. Consistent with this finding, intratumoral delivery of VNP20009 also increase caspase-3 activity and the expression of Bax protein. In summary, we revealed that VNP20009 is a promising bacterial agent for the treatment of PDAC, and that we have established a dual fluorescent imaging system as a valuable tool for noninvasive live imaging of solid tumor and engineered bacterial drug.

Oral Delivery of Tumor-Targeting Salmonella to Treat Cancer in Mice

Tumor-targeting bacteria have been developed as novel anticancer agents recently. To achieve their therapeutic effects, bacteria have conventionally been injected intravenously or intraperitoneally into animals or humans. Here, we describe the oral delivery of tumor-targeting Salmonella for cancer therapy in a mouse tumor model. We detail the experimental procedures for establishing a mouse tumor model, preparing bacterial culture, mouse gavage, and detection of the tumor-targeting capability of bacteria administered orally. We also discuss technical notes and provide practical advice that will help the users of this oral delivery model.

ECT2 regulates the Rho/ERK signalling axis to promote early recurrence in human hepatocellular carcinoma

BACKGROUND & AIMS

Early recurrence is the major obstacle for improving the outcome of patients with hepatocellular carcinoma (HCC). Therefore, identifying key molecules contributing to early HCC recurrence can enable the development of novel therapeutic strategies for the clinical management of HCC. Epithelial cell transforming sequence 2 (ECT2) has been implicated in human cancers, but its function in HCC is largely unknown.

METHODS

ECT2 expression was studied by microarrays, immunoblotting and immunohistochemistry in human HCC samples. siRNA- and lentiviral vector-mediated knockdown were employed to decipher the molecular functions of ECT2.

RESULTS

The upregulation of ECT2 is significantly associated with early recurrent HCC disease and poor survival. Knockdown of ECT2 markedly suppressed Rho GTPases activities, enhanced apoptosis, attenuated oncogenicity and reduced the metastatic ability of HCC cells. Moreover, knockdown of ECT2 or Rho also suppressed ERK activation, while the silencing of Rho or ERK led to a marked reduction in cell migration. Stable knockdown of ECT2 in vivo resulted in significant retardation of tumour growth and the suppression of ERK activation. High expression of ECT2 correlates with high ERK phosphorylation and poor survival of HCC patients. Furthermore, ECT2 enhances the expression and stability of RACGAP1, accelerating ECT2-mediated Rho activation to promote metastasis.

CONCLUSIONS

ECT2 is closely associated with the activation of the Rho/ERK signalling axis to promote early HCC recurrence. In addition, ECT2 can crosstalk with RACGAP1 to catalyse the GTP exchange involved in Rho signalling to further regulate tumour initiation and metastasis.

Expression of recombinant protein using Corynebacterium Glutamicum: progress, challenges and applications

Corynebacterium glutamicum (C. glutamicum) is a highly promising alternative prokaryotic host for recombinant protein expression, as it possesses several significant advantages over Escherichia coli (E. coli), the currently leading bacterial protein expression system. During the past decades, several experimental techniques and vector components for genetic manipulation of C. glutamicum have been developed and validated, including strong promoters for tightly regulating target gene expression, various types of plasmid vectors, protein secretion systems and methods of genetically modifying the host strain genome to improve protein production potential. This review critically discusses current progress in establishing C. glutamicum as a host for recombinant protein expression, and examines, in depth, some successful case studies of actual application of this expression system. The established "expression tool box" for developing novel constructs based on C. glutamicum as a host are also evaluated. Finally, the existing issues and solutions in process development with C. glutamicum as a host are specifically addressed.

Tumor-specifically hypoxia-induced therapy of SPRY1/2 displayed differential therapeutic efficacy for melanoma

Activation of receptor tyrosine kinase (RTK) signalling pathways is frequently correlated to cancer cell proliferation, angiogenesis and cell survival. Sprouty (SPRY) proteins function as a physiological endogenous inhibitor of RTK signalling pathways, have been shown to be deregulated in most cancer cells. Here, we demonstrated that over-expression of SPRY1 and SPRY2 inhibited B16F10 cell proliferation through G1 phase arrest in vitro, and SPRY2 showed more potent inhibitory effects than SPRY1. In order to tumor-specific delivery of SPRY1/2 in vivo, two strains of attenuated Salmonella typhimurium VNP20009 (VNP-PQE-SPRY1 and VNP-PQE-SPRY2) were constructed to specifically express SPRY1 or SPRY2 under the control of a hypoxia-induced nirB promoter. The efficiency and specificity of the recombinant strains were validated in both bacteria and animal tumor models. SPRY1 and SPRY2 gene could be specifically driven by the nirB promoter under hypoxia, but not normoxia conditions. In addition, the tumor-targeting ability of VNP-PQE-SPRY1 or VNP-PQE-SPRY2 was similar with VNP. VNP-PQE-SPRY2 significantly suppressed melanoma growth in vivo, suggesting that SPRY2 is a more efficient agent for melanoma therapy. Moreover, the antitumor effect of VNP-SPRY2 is mainly mediated through the inhibition of ERK1/2 phosphorylation, which leads to the inhibition of proliferation in melanoma. Taken together, our results indicated that SPRY2 displayed more potent melanoma suppression than SPRY1 both in vitro and in vivo, and the hypoxia-induced tumor-specific gene therapy of SPRY2 delivered by VNP20009 is a promising strategy for melanoma therapy.

Complete proteome of a quinolone-resistant Salmonella Typhimurium phage type DT104B clinical strain

Salmonellosis is one of the most common and widely distributed foodborne diseases. The emergence of Salmonella strains that are resistant to a variety of antimicrobials is a serious global public health concern. Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) is one of these emerging epidemic multidrug resistant strains. Here we collate information from the diverse and comprehensive range of experiments on Salmonella proteomes that have been published. We then present a new study of the proteome of the quinolone-resistant Se20 strain (phage type DT104B), recovered after ciprofloxacin treatment and compared it to the proteome of reference strain SL1344. A total of 186 and 219 protein spots were recovered from Se20 and SL1344 protein extracts, respectively, after two-dimensional gel electrophoresis. The signatures of 94% of the protein spots were successfully identified through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). Three antimicrobial resistance related proteins, whose genes were previously detected by polymerase chain reaction (PCR), were identified in the clinical strain. The presence of these proteins, dihydropteroate synthase type-2 (sul2 gene), aminoglycoside resistance protein A (strA gene) and aminoglycoside 6'-N-acetyltransferase type Ib-cr4 (aac(6')-Ib-cr4 gene), was confirmed in the DT104B clinical strain. The aac(6')-Ib-cr4 gene is responsible for plasmid-mediated aminoglycoside and quinolone resistance. This is a preliminary analysis of the proteome of these two S. Typhimurium strains and further work is being developed to better understand how antimicrobial resistance is developing in this pathogen.

A Salmonella Typhimurium mutant strain capable of RNAi delivery: higher tumor-targeting and lower toxicity

Bacteria are highly versatile and useful tools that could deliver short interfering RNA. In this study, a phoP/phoQ double-deleted Salmonella Typhimurium named VNP(PhoP/Q(-)) based on the genetic background of VNP20009. The biological safety and function of VNP(PhoP/Q(-)) were also analyzed. Our study revealed the following results: (1) VNP(PhoP/Q(-)) exhibited lower titers in tumor-free livers and spleens than VNP20009, (2) The survival of VNP(PhoP/Q(-)) in macrophages and 4T1 tumor cells was significantly reduced compared with that of VNP20009, (3) The tumor-targeting ability of VNP(PhoP/Q(-)) was significantly enhanced compared with that of VNP20009, and the anticancer effects of VNP(pPhoP/Q(-)) and VNP20009 on tumor-bearing mice were similar, (4) VNP(PhoP/Q(-)) could release an shRNA-expressing plasmid and express the EGFP reporter gene in tumor tissue. Therefore, VNP(PhoP/Q(-)) exhibited a better safety level in tumor-free mice and elicited an anti-tumor effect on tumor-bearing mice. Moreover, VNP(PhoP/Q(-)) could release an shRNA-expressing plasmid into the cytoplasm of host cells to silence targeted genes.

Suppression of tumor angiogenesis by targeting the protein neddylation pathway

Inhibition of protein neddylation, particularly cullin neddylation, has emerged as a promising anticancer strategy, as evidenced by the antitumor activity in preclinical studies of the Nedd8-activating enzyme (NAE) inhibitor MLN4924. This small molecule can block the protein neddylation pathway and is now in clinical trials. We and others have previously shown that the antitumor activity of MLN4924 is mediated by its ability to induce apoptosis, autophagy and senescence in a cell context-dependent manner. However, whether MLN4924 has any effect on tumor angiogenesis remains unexplored. Here we report that MLN4924 inhibits angiogenesis in various in vitro and in vivo models, leading to the suppression of tumor growth and metastasis in highly malignant pancreatic cancer, indicating that blockage of angiogenesis is yet another mechanism contributing to its antitumor activity. At the molecular level, MLN4924 inhibits Cullin–RING E3 ligases (CRLs) by cullin deneddylation, causing accumulation of RhoA at an early stage to impair angiogenic activity of vascular endothelial cells and subsequently DNA damage response, cell cycle arrest and apoptosis due to accumulation of other tumor-suppressive substrates of CRLs. Furthermore, we showed that inactivation of CRLs, via small interfering RNA (siRNA) silencing of its essential subunit ROC1/RBX1, recapitulates the antiangiogenic effect of MLN4924. Taken together, our study demonstrates a previously unrecognized role of neddylation in the regulation of tumor angiogenesis using both pharmaceutical and genetic approaches, and provides proof of concept evidence for future development of neddylation inhibitors (such as MLN4924) as a novel class of antiangiogenic agents.

Comparative proteomics analysis reveals roles for FADD in the regulation of energy metabolism and proteolysis pathway in mouse embryonic fibroblast

Fas-associated death domain-containing protein (FADD) is a classical apoptotic pathway adaptor. Further studies revealed that it also plays essential roles in nonapoptotic processes, which is assumed to be regulated by its phosphorylation. However, the exact mechanisms are still poorly understood. To study the nonapoptotic effects of FADD, a comprehensive strategy of proteomics identification combined with bioinformatic analysis was undertaken to identify proteins differentially expressed in three cell lines containing FADD and its mutant, FADD-A and FADD-D. The cell lines were thought to bear wild-type FADD, unphosphorylated FADD mimic and constitutive phosphorylated FADD mimic, respectively. A total of 47 proteins were identified to be significantly changed due to FADD phosphorylation. Network analysis using MetaCore™ identified a number of changed proteins that were involved in cellular metabolic process, including lipid metabolism, fatty acid metabolism, glycolysis, and oxidative phosphorylation. The finding that FADD-D cell line showed an increase in fatty acid oxidation argues that it could contribute to the leaner phenotype of FADD-D mice as reported previously. In addition, six proteins related to the ubiquitin-proteasome pathway were also specifically overexpressed in FADD-D cell line. Finally, the c-Myc gene represents a convergent hub lying at the center of dysregulated pathways, and was upregulated in FADD-D cells. Taken together, these studies allowed us to conclude that impaired mitochondrial function and proteolysis might play pivotal roles in the dysfunction associated with FADD phosphorylation-induced disorders.

Systemic administration of attenuated Salmonella typhimurium in combination with interleukin-21 for cancer therapy

Attenuated Salmonella typhimurium (S. typhimurium) strain VNP20009 has been employed as a powerful anticancer agent due to its selective accumulation in tumors for targeted therapy. S. typhimurium has been demonstrated to constitute a delivery tool carrying antiangiogenic or proapoptotic genes that treat cancer. The hydrodynamic tail vein (HTV) injection of naked plasmid DNA has been developed as an effective gene delivery strategy, which has been successfully used in vivo. The aim of this study was to develop a combination therapy of S. typhimurium VNP20009 and HTV injection of interleukin-21 (IL-21) expression plasmid to evaluate the antitumor potential on an experimental melanoma model. Consistent with previous results, single VNP20009 treatment was demonstrated to possess effective activities to suppress tumor growth and prolong animal survival. Moreover, HTV injection of IL-21 plasmid promoted the antitumor activities of VNP20009. The mice that were administered combined therapy exhibited smaller tumor sizes and longer survival time compared with those administered VNP20009 or IL-21 treatment alone. IL-21 induced more infiltrating natural killer (NK) and T cells to the tumor area. These findings indicated that S. typhimurium in combination with IL-21 promotes antitumor immune responses, suggesting a novel strategy in the treatment of cancer.

Preparation, cellular uptake and angiogenic suppression of shikonin-containing liposomes in vitro and in vivo

Shikonin has anticancer activity, but it has not yet been applied into clinical use. In the present study, shikonin was prepared using liposomes. We aimed to examine several aspects of sh-L (shikonin-containing liposomes): preparation, angiogenic suppression and cellular uptake through self-fluorescence. Sh-L were prepared using soybean phospholipid and cholesterol to form the membrane and shikonin was encapsulated into the phospholipid membrane. Three liposomes were prepared with shikonin. They had red fluorescence and were analysed using a flow cytometer. Angiogenic suppression of sh-L was determined using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide], Transwell tests, chick CAM (chorioallantoic membrane) and Matrigel™ plug assay. MTT assay showed the median IC₅₀ (inhibitory concentrations) as follows: shikonin, sh-L₁ and sh-L₂ were 4.99±0.23, 5.81±0.57 and 7.17±0.69 μM, respectively. The inhibition rates of migration were 53.58±7.05, 46.56±4.36 and 41.19±3.59% for 3.15 μM shikonin, sh-L₁ and sh-L₂, respectively. The results of CAM and Matrigel plug assay demonstrated that shikonin and sh-L can decrease neovascularization. Effect of shikonin was more obvious than sh-L at the same concentration. The results showed that sh-L decreased the toxicity, the rate of inhibition of migration and angiogenic suppression. The cellular uptake of the sh-L could be pictured because of the self-fluorescence. The self-fluorescence will be useful for conducting further research. Sh-L might be an excellent preparation for future clinical application to cancer patients.