腺病毒介导的p53抑制肝癌生长的实验研究

目的探讨外源性野生型Ｐ５３（Ｗｉｌｄ－ｔｙｐｅ ｐ５３, ＷＴ－ｐ５３）基因对肝癌细胞生长的影响。方法通过表达ＷＴ－ｐ５３的重组腺病毒载体（Ａｄ－ｐ５３）,将ｐ５３基因导入肝癌细胞株中,用ＭＴＴ法检测Ａｄ－ｐ５３对各细胞株生长特性的影响,流式细胞仪分析各组细胞中ＤＮＡ含量及凋亡的比例。建立裸小鼠移植瘤模型后,瘤内注射Ａｄ－ｐ５３。最后处死动物,移植瘤称重, ｗｅｓｔｅｒｎ　ｂｌｏｔ检测ｐ５３和ｐ２１蛋白的表达情况。结果外源性ｐ５３基因的导入可导致肝癌细胞生长的明显抑制,表现为既诱导细胞凋亡,又诱导细胞周期阻滞。瘤内注射Ａｄ－ｐ５３后移植瘤生长明显受抑制,并出现瘤组织中ｐ５３和ｐ２１蛋白表达的上调。结论腺病毒介导的ｐ５３基因治疗能有效控制肝癌的生长。     

Human lymphoblastoid interferon: In vitro and in vivo studies in hepatocellular carcinoma

We have examined the growth inhibitory effects of human lymphoblastoid interferon (IFN) on the human hepatocellular carcinoma (HCC) cell line PLC/PRF/5. In vitro, PLC/PRF/5 cells were sensitive to the antiproliferative effects of IFN, growth inhibition being noted at concentrations as low as 1.25 i.u. ml-1. Athymic mice with xenografted tumours derived from the PLC/PRF/5 cell line were treated daily with IFN or a saline control. An IFN dose of 2 X 10(5) i.u./day was found capable of significantly slowing tumour growth rate and prolonging mouse survival. Further studies to examine the mechanisms involved in growth inhibition in vivo demonstrated that IFN was capable of inducing the activity of the enzyme 2,5-oligoadenylic acid (2,5 A) synthetase, a potent inhibitor of protein synthesis, in tumour xenografts but not in mouse tissue, and that IFN significantly enhanced the membrane display of HLA class I glycoproteins on tumour cells, though histology did not reveal any increase in tumour infiltration by host lymphocytes. We conclude that IFN exerts potent growth inhibitory effects on the HCC cell line PLC/PRF/5 both in vitro and in vivo and its mode of action in this animal model system appears to be predominantly mediated by a direct antiproliferative effect on tumour cells.     

Angiostatin gene transfer: Inhibition of tumor growth in vivo by blockage of endothelial cell proliferation associated with a mitosis arrest

The antitumoral effects that follow the local delivery of the N-terminal fragment of human plasminogen (angiostatin K3) have been studied in two xenograft murine models. Angiostatin delivery was achieved by a defective adenovirus expressing a secretable angiostatin K3 molecule from the cytomegalovirus promoter (AdK3). In in vitro studies, AdK3 selectively inhibited endothelial cell proliferation and disrupted the G₂/M transition induced by M-phase-promoting factors. AdK3-infected endothelial cells showed a marked mitosis arrest that correlated with the down-regulation of the M-phase phosphoproteins. A single intratumoral injection of AdK3 into preestablished rat C6 glioma or human MDA-MB-231 breast carcinoma grown in athymic mice was followed by a significant arrest of tumor growth, which was associated with a suppression of neovascularization within and at the vicinity of the tumors. AdK3 therapy also induced a 10-fold increase in apoptotic tumor cells as compared with a control adenovirus. Furthermore, we showed that systemic injection of AdK3 delayed C6 tumor establishment and growth, confirming that angiostatin can function in a paracrin manner. Our data support the concept that targeted antiangiogenesis, using adenovirus-mediated gene transfer, represents a promising alternative strategy for delivering antiangiogenic factors as their bolus injections present unsolved pharmacological problems.     

Statin-AE: a novel angiostatin-endostatin fusion protein with enhanced antiangiogenic and antitumor activity

The combination of angiostatin and endostatin has been shown to have synergistic antiangiogenic and antitumor effects when the genes for these proteins are delivered to tumor cells by retroviral gene transfer. Here we report the construction of a murine angiostatin–endostatin fusion gene (Statin-AE) which shows enhanced antiangiogenic activity on human umbilical vein endothelial cell (HUVEC) tube formation in vitro compared with angiostatin or endostatin alone. Similarly, the fusion gene demonstrates antiangiogenic effects in vivo and antitumor activity in a B16F10 melanoma model when co-delivered by retroviral packaging cell inoculation in mice. The fusion gene demonstrates significantly greater inhibition of tumor growth compared with angiostatin, endostatin or the combination of genes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Combined endostatin/sFlt-1 antiangiogenic gene therapy is highly effective in a rat model of HCC

Hepatocellular carcinoma (HCC) is regarded as a suitable target for antiangiogenic strategies. However, antiangiogenic agents aimed at single targets can be neutralized by upregulation of other proangiogenic factors. Therefore, combined approaches addressing at least two angiogenic targets should be more effective. Employing an appropriate rat hepatoma model, we examined the effects of sFlt-1 (soluble vascular endothelial growth factor [VEGF] receptor 1 as an indirect inhibitor of angiogenesis) and endostatin (a direct inhibitor of angiogenesis) in both single-agent as well as combined approaches under in vitro and in vivo conditions. Similar to human HCC, rat Morris hepatoma (MH) cells secreted high levels of VEGF, but no endogenous sFlt-1. Parental MH or MHES(r) cells, stably expressing rat endostatin, were adenovirally transduced either with AdsFlt-1 (encoding sFlt-1) or control vector Adnull (containing no transgene), followed by subcutaneous inoculation into syngeneic ACI rats. Compared with MH/Adnull cells, expressing no antiangiogenic factors at all, tumor weights were reduced fourfold in the MHES(r)/Adnull group, 19-fold in the MH/AdsFlt-1-group, and 77-fold in the MHES(r)/AdsFlt-1 combination therapy group. Analysis of variance did not show a significant interaction between the effects of the two factors ES(r) and sFlt-1; their effects multiplied. In conclusion, combined expression of sFlt-1 and endostatin effectively suppresses HCC growth under in vivo conditions. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).     

Human pituitary tumor-transforming gene induces angiogenesis

Angiogenesis is a key determinant and rate-limiting step in tumor progression and metastatic spread. As pituitary tumor-transforming gene (PTTG) induces basic fibroblast growth factor (bFGF), we tested angiogenesis induced by conditioned medium (CM) derived from NIH-3T3 transfectants overexpressing wild-type human PTTG (WT-hPTTG-CM). We also examined the relationship between PTTG expression and tumor vascularity in a series of human tumors. CM from Wt-hPTTG transfectants induced proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. The bFGF concentration in WT-hPTTG-CM was elevated (10.5 +/- 0.56) compared with CM from nontransfected NIH-3T3 cells (3.3 +/- 0.56 pg/mL), and addition of anti-bFGF antibody to CM abrogated these angiogenesis markers (P < 0.01). In vivo, concentrated WT-hPTTG-CM induced chick chorioallantoic membrane spoke-wheel-like appearances. Moreover, CM derived from hPTTG transfectants harboring a point mutation on the C-terminus proline-rich region of PTTG induced weaker angiogenic activity than WT-hPTTG-CM (P < 0.01). Thus, human PTTG induces an angiogenic phenotype in both in vitro and in vivo angiogenesis models, and high PTTG messenger ribonucleic acid is associated with an angiogenic phenotype in human tumors. These PTTG-directed angiogenic actions may be mediated through bFGF, which also contributes to tumor growth.     

抑癌基因TIP30/CC3对肿瘤细胞生长的影响

目的 将TIP30/CC3基因转染肝癌细胞PLC/PRF/5并筛选稳定表达的克隆,观察TIP30/CC3基因对其生长及细胞周期变化的影响。 方法 将正、反义TIP30/CC3基因导入PLC/PRF/5肝癌细胞并筛选稳定表达的克隆;绘制细胞生长曲线并检测细胞周期变化;将筛选的PLC/PRF/5细胞接种裸鼠皮下观察致瘤性及肿瘤生长。 结果 与转染正义TIP30/CC3基因的PLC/PRF/5细胞相比,转染反义的细胞生长明显加快,转染后第3天,PLC-anti-TIP30存活细胞数为14.0×104,与PLC-pcDNA3和PLC/PRF/5两对照组比较差异有统计学意义(P<0.05);PLC-TIP30组细胞数为4.9×104,与两对照组比较细胞数少,差异有统计学意义(P<0.05)。接种后第6天,PLC-anti-TIP30组细胞数为25.0×104,与两对照组比较差异有统计学意义(P<0.01);PLC-TIP30组细胞数为12.4×104,与两对照组比较差异有统计学意义(P<0.05)。细胞周期检测显示PLC-anti-TIP30组细胞增殖旺盛(G0/G1期及S期细胞分别为22.4％和58.6％)(P<0.05);PLC-TIP30细胞周期发生G1期阻滞(G0/G1期及S期细胞分别为56.9％和28.7％)(P<0.05)。裸鼠皮下致瘤实验也证实了TIP30基因可使PLC/PRF/5细胞的致瘤性降低,裸鼠皮下成瘤时间延迟,肿瘤生长相对延缓;而PLC-anti-TIP30细胞的致瘤性增强,裸鼠皮下成瘤时间缩短,肿瘤生长加快(P<     

Interferon alpha receptors are important for antiproliferative effect of interferon-α against human hepatocellular carcinoma cells

Aim: Interferon (IFN)-alpha is a promising drug for the prevention and treatment of hepatocellular carcinoma (HCC). We reported that responders to IFN-alpha/5-fluorouracil combination therapy expressed higher IFN alpha receptor (IFNAR)2 in tumor. Herein we studied involvement of IFNARs in response to IFN-alpha in HCC cells. Methods: IFN-alpha sensitivity and expression of IFNARs were studied in six HCC cell lines (HuH7, PLC/PRF/5, HLE, HLF, HepG2, Hep3B) using growth-inhibitory and RT-PCR, Western blot assays. Short interfering RNAs (SiRNAs) against IFNAR1 and 2 were used to analyze the role of the IFNARs in IFN-alpha's effect and signal transduction. Results: The expressions of IFNAR1 and 2c mRNAs were higher in PLC/PRF/5 cells than those in other cell lines, and PLC/PRF/5 cells expressed abundant IFNAR2c on their cell membrane. When we examined the sensitivity of the HCC cell lines to the growth-inhibitory effect of IFN-alpha, PLC/PRF/5 exhibited a significant response, while the other cells were much more resistant. Knockdown of either IFNAR1 or 2 using siRNAs suppressed the IFN-alpha's signal transduction (2.5-fold), and decreased the growth-inhibitory effect (down by 69.9% and 67.3%). Conclusion: The results suggest that the expression of IFNAR1 and IFNAR2c independently are important for the antiproliferative effect of IFN-alpha in HCC cells.     

Expression of Rab5a in hepatocellular carcinoma: Possible involvement in epidermal growth factor signaling

Aim: The Rab subfamily plays a role in intracellular transport. Rab5a is, in particular, involved in receptor-mediated endocytosis. Epidermal growth factor (EGF) is known to induce cell migration and promote invasion and angiogenesis. The EGF receptor (EGFR) is actively internalized upon the addition of EGF. The aim of the present study was to clarify the expression of Rab5a in hepatocellular carcinomas (HCC) and to examine its effect on EGF signaling. Methods: The expression of the Rab5a protein in HCC and corresponding non-tumorous tissues from 23 patients with HCC who had undergone surgical resection were analyzed by immunoblotting. A stable transfectant of Rab5a dominant negative (S34N) was established in a human hepatoma cell line, PLC/PRF/5 (PLC/PRF/5/Rab5aDN). Results: High expression (tumor/non-tumor (T/N) ratios >/= 1) of Rab5a protein in HCC compared to the paired non-tumortissues was recognized in 15 patients (65.2%) of 23 samples. The Rab5a antigen was diffusely expressed in the cytoplasm and membranes of the cancer cells. The membrane-associated Rab5a is also enhanced via overexpression in HCC. The EGF-induced endocytosis of EGFR and the phosphorylation of MAP kinase were inhibited in PLC/PRF/5/Rab5aDN cells. The migration of PLC/PRF/5/Rab5aDN cells induced by EGF was also significantly attenuated. Conclusions: These results indicate that the overexpression of Rab5a in HCC may play an important role in EGF signaling.     

Inhibition of autophagy significantly enhances combination therapy with sorafenib and HDAC inhibitors for human hepatoma cells

AIM:To clarify whether histone deacetylase inhibitors histone deacetylase inhibitors(HDACIs)can sensitize hepatocellular carcinoma(HCC)cells to sorafenib treatment.METHODS:Bax,Bcl-2,ATG5-ATG12,p21,and p27protein levels in Hep3B,HepG2,and PLC/PRF/5 cells were examined by Western blot.CCK8 and a fluorometric caspase-3 assay were used to examine cellular viability and apoptosis levels.The effect of Beclin-1 on sensitization of HCC cells to sorafenib was examined by transfecting Beclin-1 siRNA into Hep3B,HepG2,and PLC/PRF/5 cells.RESULTS:Autophagy inhibition enhances the inhibitory effects of vorinostat and sorafenib alone or in combination on HCC cell growth.Vorinostat and sorafenib synergistically induced apoptosis and cell cycle alterations.Western blot data indicated that HDACIs and Beclin-1 knockdown increased the p53 acetylation level.The knockdown of Beclin-1 enhanced the synergistic effect of the combination of vorinostat with sorafenib.CONCLUSION:HDACIs can sensitize HCC cells to sorafenib treatment by regulating the acetylation level of Beclin-1.     

Adeno-associated virus-mediated expression of apolipoprotein (a) kringles suppresses hepatocellular carcinoma growth in mice

Hepatocellular carcinoma (HCC) constitutes more than 90% of all primary liver cancers. HCC is a hypervascular tumor that develops from dedifferentiation of small avascular HCC and is therefore a good target for anti-angiogenic gene therapy. Recent studies have identified apolipoprotein(a) [apo(a)] kringles LK68 and LK8 (LKs) as having a potential antiangiogenic and anti-tumor activity, and the current study evaluates the therapeutic potential of gene therapy with recombinant adeno-associated virus carrying genes encoding LKs (rAAV-LK) in the treatment of hypervascular HCC. We generated rAAV-LK to obtain persistent transgene expression in vivo, which is essential for anti-angiogenic therapy. The rAAV-produced LKs substantially inhibited proliferation and migration of human umbilical vein endothelial cells (HUVECs) in vitro, validating their anti-angiogenic potential. Intramuscular administration of rAAV-LK gave 60% to 84% suppression (P < .05) of tumor growth in mice bearing subcutaneously transplanted HCC derived from Huh-7 and Hep3B cells, respectively. Histological and immunohistochemical analyses of HCC tumor sections showed that a single administration of rAAV-LK gave rise to persistent expression of LKs that inhibited tumor angiogenesis and triggered tumor apoptosis, and, thus, significantly suppressed tumor growth. The administration of rAAV-LK provided a significant survival benefit (P < .05), and 3 of 10 rAAV-LK-treated mice were still alive without visible tumors and without clinical symptoms 188 days after treatment. In conclusion, rAAV-LK is a potential candidate for anti-angiogenic gene therapy in the treatment of HCC.     

Effects and mechanisms of silibinin on human hepatoma cell lines

AIM To investigate in vitro effects and mechanisms of silibinin on hepatocellular carcinoma (HCC) cell growth. METHODS Human HCC cell lines were treated with different doses of silibinin. The effects of silibinin on HCC cell growth and proliferation, apoptosis, cell cycle progression, histone acetylation, and other related signal transductions were systematically examined. RESULTS We demonstrated that silibinin significantly reduced the growth of HUH7, HepG2, Hep3B, and PLC/PRF/5 human hepatoma cells. Silibinin-reduced HuH7 cell growth was associated with significantly upregulated p21/CDK4 and p27/CDK4 complexes, downregulated Rb-phosphorylation and E2F1/DP1 complex. Silibinin promoted apoptosis of HuH7 cells that was associated with down-regulated survivin and upregulated activated caspase-3 and -9. Silibinin's anti angiogenic effects were indicated by down-regulated metalloproteinase-2 (MMP2) and CD34. We found that silibinin-reduced growth of HuH7 cells was associated with increased activity of phosphatase and tensin homolog deleted on chromosome ten (PTEN) and decreased p-Akt production, indicating the role of PTEN/ PI3K/Akt pathway in silibinin-mediated anti-HCC effects. We also demonstrated that silibinin increased acetylation of histone H3 and H4 (AC-H3 and AC-H4), indicating a possible role of altered histone acetylation in silibininreduced HCC cell proliferation.CONCLUSION Our results defined silibinin's in vitro anti-HCC effects and possible mechanisms, and provided a rationale to further test silibinin for HCC chemoprevention.     

Doxorubicin conjugates of monoclonal antibodies to hepatoma-associated antigens.

A panel of six murine monoclonal antibodies against hepatocellular carcinoma-associated antigens, reactive with PLC/PRF/5 human hepatoma cells, was conjugated to Adriamycin (doxorubicin) via a dextran bridge. This library of antibodies includes three monoclonal antibodies against hepatitis B virus surface antigen, one anti-alpha-fetoprotein, and two other IgG2a antibodies against PLC/PRF/5 hepatoma-associated antigens. The use of dextran for conjugation of Adriamycin to antibodies enabled a 5- to 10-fold amplification of the number of drug molecules linked to antibody. Conjugation of Adriamycin to dextran caused an occasional reduction in the pharmacologic activity of dextran-Adriamycin in [3H]thymidine incorporation assays in hepatoma cells as compared to nonconjugated Adriamycin. This loss of anticellular activity was partially compensated for by conjugation of specific antibodies to the dextran-Adriamycin conjugate. Conjugated compounds completely retained their binding activity to purified hepatitis B virus surface antigen and alpha-fetoprotein fixed to a solid matrix as compared to binding of homologous nonconjugated antibodies. However, some reduction of the binding activity to intact hepatoma cells was observed in three of six conjugates. Binding activity to hepatoma cells and, as a consequence, suppression of tumor cell DNA synthesis by the various conjugates was enhanced as compared to the same effect in treated colorectal carcinoma cells that do not express the relevant hepatoma-associated proteins. Furthermore, two conjugates containing nonspecific antibodies did not bind to hepatoma cells and caused minimal suppression of DNA synthesis. These results suggest that this panel of monoclonal antibody-dextran-Adriamycin conjugates was effective in suppression of PLC/PRF/5 cell growth in vitro.     

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.     

Gene therapy for hepatocellular carcinoma: augmentation of thymidine kinase gene/ganciclovir system using chemical modulators of nuclear proteins

A Moloney murine leukemia virus-derived retroviral vector carrying the herpes simplex virus (HSV) thymidine kinase (TK) gene was constructed and subsequently transfected into Ψ2 packaging cells, with resultant retrovims being transduced into XC rat hepatoma cells. Using HSV-TK gene-transduced XC (XCtkn) cells, we studied the effects of treatment with GCV, as well as with GCV and anticancer drugs or chemical modulators of nuclear proteins. GCV treatment was also examined in co-cultures of XCtkn cells and genetically unmodified XC, PLC/PRF/5 and Huh1 hepatoma cells, respectively. The growth of HSV-TK gene-transduced XC (XCtkn) cells either in vivo or in vitro was suppressed by treating with ganciclovir (GCV). In addition, the proliferation of genetically unmodified XC, PLC/PRF/5 and Huhl hepatoma cells was inhibited on co-culturing in vitro with the XCtkn cells and GCV, indicating that bystander effect operated in the present experimental system. Anticancer drugs and chemical modulators of nuclear proteins acted additively with GCV in inhibiting the proliferation of XCtkn cells. These suggest that the use of HSV-TK/GCV system in combination with other drugs may be a promising therapy for hepatocellular carcinoma.     

二甲双胍对肝癌PLC/PRF/5肿瘤干细胞增殖分化、凋亡、迁移的影响

目的:探究二甲双胍对肝癌PLC/PRF/5肿瘤干细胞(CSC)增殖分化、凋亡、迁移的影响。方法:体外特殊条件培养法培养PLC/PRF/5 CSC细胞,用不同浓度(5、10、20 mmol/L)二甲双胍处理PLC/PRF/5 CSC,以未进行处理的PLC/PRF/5 CSC为对照组,在显微镜下观察细胞形态;CCK-8法检测各组细胞活力;流式细胞术检测各组细胞凋亡率;划痕实验检测各组细胞迁移能力;蛋白免疫印迹法检测各组细胞蛋白表达情况;构建裸鼠肝癌移植瘤模型,检测二甲双胍对PLC/PRF/5 CSC成瘤能力的影响。结果:PLC/PRF/5 CSC具有成球能力,经二甲双胍处理后,PLC/PRF/5成球细胞数目显著减少;同一时间段,与对照组比较,二甲双胍处理组细胞活力显著降低,且呈剂量依赖性(P<0.05),随着处理时间的增加,各组细胞活力逐渐降低;与对照组比较,二甲双胍处理组细胞凋亡率、凋亡蛋白Caspase-3、Caspase-9、迁移蛋白E-cadherin的表达显著升高,细胞迁移率、细胞干性基因Oct4、Nanog蛋白表达、迁移蛋白N-cadherin的表达显著降低,且呈剂量依赖性(P<0.05);与对照组比较,随着接种时间的增加,二甲双胍处理组裸鼠肿瘤生长速度较慢(P<0.05),且随着二甲双胍浓度的增加,裸鼠肿瘤生长速度逐渐变慢。结论:二甲双胍能够抑制肝癌PLC/PRF/5 CSC的增殖和迁移,促进其凋亡,可能是靶向肝癌CSC治疗的潜在药物。     

Efficacy of a novel histone deacetylase inhibitor in murine models of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer death worldwide, yet effective therapeutic options for advanced HCC are limited. This study was aimed at assessing the antitumor effect of a novel phenylbutyrate-derived histone deacetylase (HDAC) inhibitor, OSU-HDAC42, vis-à-vis suberoylanilide hydroxamic acid (SAHA), in in vitro and in vivo models of human HCC. OSU-HDAC42 was several times more potent than SAHA in suppressing the viability of PLC5, Huh7, and Hep3B cells with submicromolar median inhibitory concentration (IC(50)) values. With respect to SAHA, OSU-HDAC42 exhibited greater apoptogenic potency, which was associated with reduced levels of the apoptotic regulators phosphorylated Akt B-cell lymphoma-xL, survivin, cellular inhibitor of apoptosis protein 1, and cellular inhibitor of apoptosis protein 2. The in vivo efficacy of OSU-HDAC42 versus SAHA was assessed in orthotopic and subcutaneous xenograft tumor models in athymic nude mice. Daily oral treatments with OSU-HDAC42 and SAHA, both at 25 mg/kg, suppressed the growth of orthotopic PLC5 tumor xenografts by 91% and 66%, respectively, and of established subcutaneous PLC5 tumor xenografts by 85% and 56%, respectively. This differential tumor suppression correlated with the modulation of intratumoral biomarkers associated with HDAC inhibition and apoptosis regulation. Moreover, the oral administration of OSU-HDAC42 at 50 mg/kg every other day markedly suppressed ectopic tumor growth in mice bearing large tumor burdens (500 mm(3)) at the start of treatment. CONCLUSION: OSU-HDAC42 is a potent, orally bioavailable inhibitor of HDAC with a broad spectrum of antitumor activity that includes targets regulating multiple aspects of cancer cell survival. These results suggest that OSU-HDAC42 has clinical value in therapeutic strategies for HCC.     

Bevacizumab enhances chemosensitivity of hepatocellular carcinoma to adriamycin related to inhibition of survivin expression

Purpose

In recent years, anti-angiogenesis drugs have shown promising clinical effects against many tumors, particularly in combination with chemotherapy. Although the combination has become a standard of care for many tumors, the mechanisms of the chemosensitizing activity of anti-angiogenic drugs are not fully understood. Here, we sought to determine if anti-angiogenesis drug bevacizumab could enhance the chemosensitivity of HCC by inhibition of survivin.

Methods

After treatment of human umbilical vein endothelial cells (HUVECs) and hepatocellular carcinoma (HCC) cell line PLC/PRF/5 (PLC) with bevacizumab or/and adriamycin, the direct effects were examined by survival assays, and the expression of Akt, Phospho-Akt and survivin were evaluated by western blot. Tumor growth was observed in a human HCC xenograft nude mouse model treated with different drugs, and the expression of PCNA, CD31 and survivin in tumor tissues were evaluated by means of immunohistochemistry.

Results

Bevacizumab enhanced the chemosensitivity of HCC by inhibiting the VEGF-PI3?K/Akt-survivin signaling cascade in endothelial cells. The combination of bevacizumab with adriamycin therapy resulted in better outcomes compared with monotherapy in hepatocellular carcinoma xenografts; bevacizumab significantly inhibited tumor angiogenesis and growth. In addition, bevacizumab reduced survivin expression in tumor tissues, including tumor vascular endothelial cells in vivo, although it did not inhibit survivin expression in tumor cells in vitro.

Conclusion

These results implicate the bevacizumab-increased efficacy of adriamycin via an inhibition of survivin expression in malignant cells as well as tumor vasculature cells, which provides other insights into the mechanism of enhanced efficacy by combination of VEGF blocker and chemotherapeutic agents.