Antiangiogenic gene therapy for hepatocellular carcinoma using angiostatin gene

Recent studies have reported that antiangiogenic gene delivery into cancer cells inhibits growth of certain tumors in vivo. Hepatocellular carcinoma (HCC) is a hypervascular cancer, and antiangiogenic gene therapy might be suitable for HCC. In the present study, we investigated the antiangiogenic effects of angiostatin gene transduction into HCC both in vitro and in vivo. Angiostatin gene was cloned into a pSecTag2B mammalian expression vector to construct pSecTag2B-ANG. pSecTag2B or pSecTag2B-ANG were transfected into an HCC cell line, PLC/PRF/5, and then stable transfectants were obtained by Zeocin selection. pSecTag2B or pSecTag2B-ANG transfection did not alter the expression of vascular endothelial growth factor (VEGF), a potent angiogenic stimulator, or pigment epithelium-derived factor (PEDF), an angiogenic inhibitor, in PLC/PRF/5 cells. However, conditioned media (CM) derived from pSecTag2B-ANG-transfected PLC/PRF/5 cells (CM-ANG) suppressed the proliferation and migration of human umbilical vein endothelial cells (HUVEC) by 35% and 50%, respectively, relative to their effects on nontransfected cells. In in vivo experiments, pSecTag2B-ANG stable transfected (CM-Mock) and nontransfected cells (CM-N) were mixed at various proportions and the mixed cells were subcutaneously implanted into athymic mice. Suppression of tumor growth was noted in mice implanted with angiostatin gene-transfected cells, and such suppression was proportional with the percentage of transfected cells. Analysis of the vascular density in these tumors showed that the tumor growth suppression effect of angiostatin gene correlated with suppression of tumor vascularity. In conclusion, antiangiogenic gene therapy using angiostatin gene is potentially suitable for the treatment of patients with HCC.     

Antiangiogenic property of pigment epithelium-derived factor in hepatocellular carcinoma

Pigment epithelium-derived factor (PEDF) is one of the most powerful endogenous antiangiogenic reagents discovered to date. Its antiangiogenic potential in neoplastic disease remains unclear. In this study, we investigated antiangiogenic property of PEDF in hepatocellular carcinoma (HCC), a typical hypervascular tumor. In HCC cell lines, constitutive messenger RNA and protein expression of PEDF varied. Genomic DNA encoding the PEDF gene was the same in the cell lines examined by Southern blotting. In chemically induced hypoxic conditions, secreted PEDF protein was suppressed in contrast to elevation of vascular endothelial growth factor protein. When PEDF was overexpressed by gene transfer, proliferation and migration of endothelial cells were inhibited in conditioned media derived from all HCC cell lines. However, the serum concentration of PEDF, as measured by enzyme-linked immunosorbent assay, was decreased in patients with cirrhosis or HCC complicated by cirrhosis compared to healthy volunteers and patients with chronic hepatitis. According to the endothelial cell proliferation assay, the serum PEDF of patients with HCC had antiangiogenic activity. Moreover, intratumoral injection of a PEDF-expressing plasmid in athymic mouse models caused significant inhibition of preestablished tumor growth. In conclusion, PEDF plays a role in the angiogenic properties of HCC. Reduction of serum PEDF concentration associated with the development of chronic liver diseases may contribute to the progression of HCC. In addition, gene therapy using PEDF may provide an efficient treatment for HCC.     

Complete eradication of hepatocellular carcinomas by combined vasostatin gene therapy and B7H3-mediated immunotherapy

BACKGROUND/AIMS: B7H3 immunogene therapy is able to completely eradicate tumors when combined with an anti-vascular agent. The aim of this study was to determine whether vasostatin, a potent anti-angiogenic agent, could synergize with B7H3-mediated immunotherapy to combat hepatocellular carcinoma (HCC). METHODS: Vasostatin and B7H3 expression plasmids were constructed, and the in vitro and in vivo expression and anti-angiogenic activity of recombinant vasostatin were measured. The anti-tumor activities of B7H3 and vasostatin alone and in combination were assessed using single and multiple H22 tumor models. RESULTS: Gene transfer of vasostatin inhibited the proliferation of aortic endothelial cells, and angiogenesis in the chorioallantoic membrane assay. Subcutaneous H22 tumors established in BALB/c mice were completely eradicated in response to intratumoral injection of B7H3-expressing plasmids followed 24h later by vasostatin-expressing plasmids. In contrast, neither vasostatin nor B7H3 monotherapy was effective. Gene transfer of vasostatin inhibited tumor angiogenesis and enhanced infiltration of NK cells, whereas B7H3 therapy activated CD8+ and NK cells and increased their infiltration into tumors, and enhanced the levels of circulating IFN-gamma. B7H3 and vasostatin combination gene therapy was effective in combating a systemic challenge of parental H22 cells, and caused the complete regression of multiple distant tumor nodules. CONCLUSIONS: Combining vasostatin anti-angiogenic therapy with B7H3-mediated immunotherapy warrants investigation as a therapeutic strategy to combat HCC, and other malignancies.     

Induction of immunosuppressive molecules and regulatory T cells counteracts the antitumor effect of interleukin-12-based gene therapy in a transgenic mouse model of liver cancer

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) often lacks curative treatment; therefore new efficient therapies are needed. In this work we aimed at evaluating the antitumor effect of interleukin-12 (IL-12)-based gene therapy on HCC occurring spontaneously in mice. METHODS: A plasmid-vector expressing IL-12 in a liver-specific and doxycycline (Dox)-inducible manner was transferred by hydrodynamic injection to the liver of L-PK/c-myc mice with HCC. IL-12 expression was induced by administering Dox (3 cycles of 1 month duration separated by 1 month rest). RESULTS: Dox administration increased serum IL-12 and IFN-gamma and induced tumor lymphocytic infiltration in all treated mice which was accompanied by tumor stabilization or regression in 40% of animals. The antitumor effect did not correlate with levels of IL-12 or IFN-gamma nor with the intensity of tumor mononuclear infiltration. However, tumors from non-responder mice showed more abundance of Foxp3+ regulatory T cells and higher expression of the immunosuppressive molecules PD-1, PD-L1, VEGF, CTLA-4, IDO, and IL-10 than those that responded to therapy. CONCLUSIONS: Although long-term induction of IL-12 expression in the liver can inhibit HCC growth, the efficacy of the treatment appears to be limited by the activation of immunosuppressive mechanisms.     

Tie2 vascular endothelial receptor expression and function in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is generally characterized as a hypervascular tumor of rapid growth. We have previously reported that angiopoietin (Ang), a ligand for Tie2 vascular endothelial-specific receptor tyrosine kinase, may play a role in the progression of human HCC (J Clin Invest 1999;103:341-345) and matrix proteinase expression (Cancer Res 2001;61:2145-2153). However, the role of Tie2 receptor in hepatic oncogenesis is unknown. The Tie2 receptor protein was overexpressed in the neovascular endothelium of 31 of 39 (80%) human HCC tumors by immunohistochemical analysis with significant correlation to cell dedifferentiation and tumor size (P <.05). In vitro expression of a dominant-negative construct, containing a soluble Tie2 ectodomain (sTie2), led to Ang protein interaction, inhibition of endogenous Tie2 phosphorylation in vascular endothelial cells and matrix metalloproteinase 9 (MMP-9) suppression. In conclusion, tumorigenicity with neovascularization was suppressed by in vivo gene transfer and sTie2 expression in a murine HCC model, suggesting a possible role for Tie2 expression in the induction of HCC neovascularization and disease progression. Inhibition of the Ang/Tie2 signal transduction cascade is a promising approach for tumor treatment.     

Macrophage activation: dissociation of cytotoxic activity from Ia-A antigen expression.

Peritoneal macrophages were obtained from DBA/2 mice that were untreated or after the injection of bacillus Calmette-Guerin (BCG), thioglycollate broth, proteose-peptone broth, or gamma-irradiated P-815 tumor cells. These macrophages were "activated" to become cytotoxic for a fibroblast cell line (L 929) by the addition of lymphokines (LKs), lipopolysaccharide (LPS), or fibroblast interferon (IFN-beta), and the expression of I region-associated antigens (Ia-Ad) on the macrophages was examined both before and after activation. Thioglycollate-elicited macrophages became Ia-A+ when activated by LKs, but they remained Ia-A- when activated by LPS or IFN-beta. Resident macrophages and proteose-peptone-elicited macrophages remained Ia-A- when activated with LKs. Macrophages from BCG-infected mice were both Ia-A+ and cytotoxic for tumor cells without further treatment. In contrast, macrophages from mice injected with gamma-irradiated P-815 mastocytoma cells were Ia-A+ but not cytotoxic, and these macrophages could not be made cytotoxic by incubation with LKs. The cultured macrophage-like cell lines P388D1 and WEHI-3 became Ia-A+ after incubation with LKs, and this treatment amplified the cytotoxicity of both cell lines. We conclude that a number of factors are important in determining whether Ia-A expression accompanies macrophage activation and that Ia-A is irrelevant as a surface marker for macrophage activation.     

Clinical value of gadoxetic acid-enhanced magnetic resonance imaging in surgery for hepatocellular carcinoma - with a special emphasis on early hepatocellular carcinoma

Gadoxetic acid- or gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) achieves excellent lesion detection and characterization for both hypervascular hepatocellular carcinoma (HCC) in arterial phase imaging and hypovascular early HCC (small well-differentiated HCC of the vaguely nodular type) in hepatobiliary phase imaging, and has become an indispensable imaging modality in the treatment of HCC. Early HCCs have been detected more frequently since the introduction of EOB-MRI into daily clinical practice. Early HCC is known to progress to conventional hypervascular HCC, and many risk factors have been identified for the hypervascularization of early HCC including the diameter of the tumor, presence of fat, and imaging findings of EOB-MRI. The rate of the development of hypervascular HCC was previously reported to be high in patients with chronic liver disease and early HCC. The presence of early HCC is regarded as a predictor for the recurrence of HCC following hepatic resection. On the other hand, although early HCC itself is currently not regarded as a target lesion for hepatic resection, early HCC at high risk of hypervascularity needs to be treated by local ablation therapy. If concomitant early HCC with progressed HCC is at high risk of hypervascularization and the functional liver reserve of a patient is sufficient, its simultaneous treatment at the time of hepatic resection for progressed HCC is recommended. Further studies on larger numbers of patients are needed before this strategy is adopted.     

Hepatocellular carcinoma--cause, treatment and metastasis

In the recent decades, the incidence of hepatocellular carcinoma (HCC) has been found to be increasing in males in some countries. In China, HCC ranked second of cancer mortality since 1990s. Hepatitis B and C viruses (HBV and HCV) and dietary aflatoxin intake remain the major causative factors of HCC. Surgery plays a major role in the treatment of HCC, particularly for small HCC. Down-staging unresectable huge HCC to smaller HCC and followed by resection will probably be a new approach for further study. Liver transplantation is indicated for small HCC, however, some issues remain to be solved. Different modes of regional cancer therapy for HCC have been tried. Systemic chemotherapy has been disappointing in the past but the future can be promising. Biotherapy, such as cytokines, differentiation inducers, anti-angiogenic agents, gene therapy and tumor vaccine will probably play a role, particularly in the prevention of tumor recurrence. HCC invasiveness is currently the major target of study. Tremendous works have been done at the molecular level, which will provide clues for biomarker of HCC progression as well as targets for intervention.     

Des-γ-carboxyl prothrombin is associated with tumor angiogenesis in hepatocellular carcinoma

Background and Aim: Hepatocellular carcinoma (HCC) is a hypervascular tumor, and angiogenesis plays an important role in its development. Previously, we demonstrated that des‐γ‐carboxyl prothrombin (DCP) promotes both cell proliferation and migration of human umbilical vein endothelial cells (HUVECs) by inducing the autophosphorylation of kinase insert domain receptor (KDR). In the present study, DCP‐associated tumor angiogenesis was assessed by comparing hypovascular and common hypervascular HCC. Methods: The solitary HCCs of 827 patients were classified into two groups according to the tumor density at the arterial phase of a dynamic computed tomography scan; the initial clinical data of patients with the hyper‐ and hypovascular types were compared. The HCC tissues from 95 tumors were analyzed by immunohistochemical staining for DCP and phosphorylated KDR, and intratumoral microvessel density (MVD) was analyzed to evaluate microvessel angiogenesis. Results: The serum DCP levels (320 ± 3532 mAU/mL) and tumor size (18.4 ± 9.0 mm) of patients with hypervascular HCC were significantly greater than those with hypovascular HCC (38.7 ± 80 mAU/mL and 14.6 ± 5.2 mm, P < 0.001). Immunohistochemical analysis revealed that the expressions of DCP and phospho‐KDR were significantly greater in hypervascular HCC (71.4% and 31.0%, respectively) than in hypovascular HCC (7.6% and 5.7%, respectively). Intratumoral MVD was significantly correlated with DCP (r = 0.48, P < 0.0001). Conclusions: des‐γ‐carboxyl prothrombin production is associated with tumor angiogenesis in HCC.     

Management of inoperable hepatocellular carcinoma

Abstract   Hepatocellular carcinoma (HCC) is a common and difficult-to-treat malignant tumor. Surgical interventions are feasible in only a small proportion of patients, and non-surgical therapy has been frequently administered to patients with inoperable HCC. Various modalities of loco-regional therapy have gained much interest during the past decade. Among them, transarterial chemoembolization (TACE), percutaneous injection of ethanol (PEI) or acetic acid (PAI), radiofrequency ablation (RFA) and microwave coagulation therapy (MCT) are effective treatment options. TACE can target multiple hypervascular tumors but has the potential risk of inducing hepatic or renal failure. PEI is a well-established method for small (< 3 cm) HCC, and PAI has the advantage over PEI as being more effective with fewer treatment sessions. RFA has excellent tumor ablation ability, and has been extended to treat medium- or large-sized HCC. However, the overall complication rate may be higher than previously assumed. MCT is similar to RFA in its clinical application and adverse effects. Although combination therapy often achieves a higher response rate, the side-effects may also be additive. Other therapies, such as injection of hot saline or yttrium-90 microspheres, interstitial laser photocoagulation and cryoablation are seldom used nowadays. Thalidomide may be useful in a minority of HCC patients, whereas radiotherapy, chemotherapy and tamoxifen are generally ineffective. In conclusion, although long-term survival in patients with inoperable HCC is possible in selected patients, the overall prognosis remains unsatisfactory, especially in those with aggressive tumor behavior. Newer antitumor therapy with better treatment efficacy is urgently needed. Information of the design for a more comprehensive approach using the existing therapeutic options may help refine the treatment strategy.     

Angiogenesis in hepatocellular carcinoma: the retrospectives and perspectives

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. Many angiogenic factors have been studied in HCC, and several anti-angiogenic therapies have been tested in animal models and patients. This paper summarizes the latest findings, especially regarding the clinical significance of endothelial cell markers and angiogenic factors in HCC, and experimental and clinical anti-angiogenesis therapies. Further developments in this area, such as endothelial cell-oriented research and better experimental and clinical designs in the evaluation of anti-angiogenic therapies are discussed. This work was jointly supported by a grant from the Shanghai Clinical Center Project, the Promising Young Doctor of Shanghai grant, and the Project 211 grant from the Ministry of Education of China     

Individualized treatment models based on blood supply characteristics in hepatocellular carcinoma using color Doppler hemodynamics

BACKGROUND/AIMS: We evaluated the long-term efficacy of the combination of transcatheter arterial chemoembolization (TACE) using cisplatin-lipiodol suspension, transultrasonic portal vein chemoembolization (SPVE), radiofrequency ablation (RF), percutaneous ethanol injection (PEI) for treatment of advanced small hepatocellular carcinoma (HCC). METHODOLOGY: A total of three hundred and eighteen patients with HCC were enrolled in this study. According to the blood supply characteristics to the tumor, individual combined therapy models were adopted: one hundred and fifty-nine patients with HCC less than 5 cm were treated with a combination of RF and PEI (RF/PEI group) and one hundred and one patients with HCC greater than 5cm were treated with a combination of TACE, RF and PEI (TACE/RF/PEI group). One hundred and eleven HCC nodules confirmed to be hypervascular by color Doppler flow imaging were treated with a combination of TACE, RF, SPVE and PEI (TACE/ RF/SPVE/PEI group). RESULTS: The combination treatment of RF and PEI (RF/PEI group), the TACE/RF/PEI group, TACE/ RF/SPVE/PEI group, the 1-year survival rates and the 3-year survival rates were 97.3% and 82.4%; 73.5% and 44.9%; 74.1% and 37.9%, respectively; The vanishing rate of blood flow around and within the tumor, the tumor size decrease rate, AFP transformed to negative rate, were significantly raised compared to those in the TACE treatment only group. CONCLUSIONS: The individual combined therapy models combination of TACE, PEI, SPVE, RF appears to prolong survival, compared with one treatment alone (TACE). This combination therapy method is an effective way for treating HCC, and color Doppler can provide important information to verify the therapeutic effects.     

Targeted IL-24 gene therapy inhibits cancer recurrence after liver tumor resection by inducing tumor cell apoptosis in nude mice

BACKGROUND:Interleukin-24(IL-24)is a novel candi-date tumor suppressor that induces tumor cell apoptosis experimentally in a variety of human malignant cells including liver cancer cells.The present study was conducted to investigate the potential effect of recombinant adeno-associated virus(rAAV)-mediated IL-24 gene therapy on tumor recurrence and metastasis by inducing tumor cell apoptosis in a hepatocellular carcinoma(HCC)model in nude mice.METHODS:We established a recurrent and metastatic HCC model in n...     

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

AIM： To evaluate the feasibility and efficacy of percutaneous radiofrequency ablation （RFA） of the feeding artery of hepatocellular carcinoma （HCC） in reducing the blood-flow-induced heat-sink effect of RFA.
METHODS： A total of 154 HCC patients with 177 pathologically confirmed hypervascular lesions participated in the study and were randomly assigned into two groups. Seventy-one patients with 75 HCCs （average tumor size, 4.3 ± 1.1 cm） were included in group A, in which the feeding artery of HCC was identified by color Doppler flow imaging, and were ablated with multiple small overlapping RFA foci [percutaneous ablation of feeding artery （PAA）] before routine RFA treatment of the tumor. Eighty-three patients with 102 HCC （average tumor size, 4.1 ± 1.0 cm） were included in group B, in which the tumors were treated routinely with RFA. Contrast-enhanced computed tomography was used as post-RFA imaging, when patients were followed-up for 1, 3 and 6 mo.
RESULTS： In group A, feeding arteries were blocked in 66 （88%） HCC lesions, and the size of arteries decreased in nine （12%）. The average number of punctures per HCC was 2.76 ± 1.12 in group A, and 3.36 ± 1.60 in group B （P = 0.01）. The tumor necrosis rate at 1 mo post-RFA was 90.67% （68/75 lesions） in group A and 90.20% （92/102 lesions） in group B. HCC recurrence rate at 6 mo post-RFA was 17.33% （13/75） in group A and 31.37% （32/102） in group B （P = 0.04）.
CONCLUSION： PAA blocked effectively the feeding artery of HCC. Combination of PAA and RFA significantly decreased post-RFA recurrence and provided an alternative treatment for hypervascular HCC.     

Interventional oncology: new options for interstitial treatments and intravascular approaches

Superselective TACE is defined as TACE from the distal portion of the feeding subsegmental hepatic artery to evoke strong ischemic effects on a small area of the liver, thus avoiding damage to liver function. Lipiodol (iodized oil) is semi-fluid, and it can flow into the surrounding portal venules and hepatic sinusoids through peribiliary plexus (PBP) and the drainage route from the hypervascular HCC. Therefore, the reversed flow from the hepatic sinusoids and portal venules to the peripheral portion of the tumor and daughter nodules can be blocked by Lipiodol injected before a particulate embolus (such as gelatin sponge particles). Common complications of superselective TACE are mild local pain and fever and temporary minimal changes of liver function. Reported CR ratio of definitely hypervascular HCC are around 30–60% by superselective TACE with Lipiodol for hypervascular HCC less than 5 cm. According to a nationwide survey by the Liver Cancer Study Group of Japan (LCSGJ), overall 5-year survival rate was 26% in patients with HCCs not indicated for surgery or RFA (PEI), mainly treated by segmental or subsegmental TACE using Lipiodol. Therefore, this TACE technique should be widely introduced as the first line technique for TACE therapy of HCC.     

MG624, an α7-nAChR antagonist, inhibits angiogenesis via the Egr-1/FGF2 pathway

Small cell lung cancer (SCLC) demonstrates a strong etiological association with smoking. Although cigarette smoke is a mixture of about 4,000 compounds, nicotine is the addictive component of cigarette smoke. Several convergent studies have shown that nicotine promotes angiogenesis in lung cancers via the α7-nicotinic acetylcholine receptor (α7-nAChR) on endothelial cells. Therefore, we conjectured that α7-nAChR antagonists may attenuate nicotine-induced angiogenesis and be useful for the treatment of human SCLC. For the first time, our study explores the anti-angiogenic activity of MG624, a small-molecule α7-nAChR antagonist, in several experimental models of angiogenesis. We observed that MG624 potently suppressed the proliferation of primary human microvascular endothelial cells of the lung (HMEC-Ls). Furthermore, MG624 displayed robust anti-angiogenic activity in the Matrigel, rat aortic ring and rat retinal explant assays. The anti-angiogenic activity of MG624 was assessed by two in vivo models, namely the chicken chorioallantoic membrane model and the nude mice model. In both of these experimental models, MG624 inhibited angiogenesis of human SCLC tumors. Most importantly, the administration of MG624 was not associated with any toxic side effects, lethargy or discomfort in the mice. The anti-angiogenic activity of MG624 was mediated via the suppression of nicotine-induced FGF2 levels in HMEC-Ls. MG624 decreased nicotine-induced early growth response gene 1 (Egr-1) levels in HMEC-Ls, and reduced the levels of Egr-1 on the FGF2 promoter. Consequently, this process decreased FGF2 levels and angiogenesis. Our findings suggest that the anti-angiogenic effects of MG624 could be useful in anti-angiogenic therapy of human SCLCs.     

Regression of established hepatocellular carcinoma is induced by chemoimmunotherapy in an orthotopic murine model

The high rate of mortality and frequent incidence of recurrence associated with hepatocellular carcinoma (HCC) reveal the need for new therapeutic approaches. In this study we evaluated the efficacy of a novel chemoimmunotherapeutic strategy to control HCC and investigated the underlying mechanism that increased the antitumor immune response. We developed a novel orthotopic mouse model of HCC through seeding of tumorigenic hepatocytes from SV40 T antigen (Tag) transgenic MTD2 mice into the livers of syngeneic C57BL/6 mice. These MTD2-derived hepatocytes form Tag-expressing HCC tumors specifically within the liver. This approach provides a platform to test therapeutic strategies and antigen-specific immune-directed therapy in an immunocompetent murine model. Using this model we tested the efficacy of a combination of oral sunitinib, a small molecule multitargeted receptor tyrosine kinase (RTK) inhibitor, and adoptive transfer of tumor antigen-specific CD8(+) T cells to eliminate HCC. Sunitinib treatment alone promoted a transient reduction in tumor size. Sunitinib treatment combined with adoptive transfer of tumor antigen-specific CD8(+) T cells led to elimination of established tumors without recurrence. In vitro studies revealed that HCC growth was inhibited through suppression of STAT3 signaling. In addition, sunitinib treatment of tumor-bearing mice was associated with suppression of STAT3 and a block in T-cell tolerance. CONCLUSION: These findings indicate that sunitinib inhibits HCC tumor growth directly through the STAT3 pathway and prevents tumor antigen-specific CD8(+) T-cell tolerance, thus defining a synergistic chemoimmunotherapeutic approach for HCC.     

Octreotide acts as an antitumor angiogenesis compound and suppresses tumor growth in nude mice bearing human hepatocellular carcinoma xenografts

Purpose To investigate the effect of octreotide on angiogenesis induced by human hepatocellular carcinoma (HCC) and to evaluate whether octreotide can suppress tumor growth in nude mice bearing human HCC xenografts through inhibition of angiogenesis.Methods Using MTT assay, invasion assay, migration assay, and Matrigel assay, the effects of octreotide on endothelial cells stimulated by vascular endothelial growth factor (VEGF) were evaluated in vitro. MTT assay was also used to investigate the effects of octreotide on human HCC cells with high (MHCC97-H) and low (MHCC97-L) metastatic potential that were established from the animal model of human HCC LCI-D20 in nude mice. The expression of somatostatin receptor (SSTR) subtypes in human umbilical vein endothelial cells (HUVECs), MHCC97-H, and MHCC97-L cells was detected by RT-PCR analysis. An LCI-D20 corneal micropocket model in nude mice was used to evaluate the effect of octreotide on angiogenesis induced by human HCC in vivo. Male nude mice were subcutaneously implanted with LCI-D20 tumor tissues for the tumor xenograft studies. Microvessel density was analyzed in CD34-stained tumor sections by the immunohistochemical SP method.Results In vitro, octreotide inhibited the proliferation, invasion, and differentiation of HUVECs elicited by VEGF. RT-PCR analysis demonstrated that HUVECs expressed the somatostatin receptor subtype SSTR3. In vivo, octreotide was sufficiently potent to suppress nude mice corneal neovascularization induced by tumor tissues from LCI-D20. Systemic administrations of octreotide produced a significant suppression of the growth of LCI-D20. In cell culture, MHCC97-H and MHCC97-L cells were insensitive to octreotide at concentrations that significantly inhibited endothelial cells proliferation. The HCC cells used did not express any known SSTRs. Immunohistochemical studies of tumor tissues revealed decreased microvessel density in octreotide-treated animals as compared with controls.Conclusions The present study demonstrates that the somatostatin analogue octreotide is a potent antitumor angiogenesis compound and the antiproliferative effect of octreotide on tumor growth in nude mice bearing HCC xenografts may be mediated, at least in part, by its suppressive effect on blood vessel supply. The somatostatin analogue octreotide might provide a useful and relatively nontoxic adjuvant therapy in the treatment of HCC.The work was supported by the grant from the Natural Science Foundation of Anhui and Anke Pharmaceutical Co. limited (NO.01043708)