The metabolite 3-hydroxiglutaric acid effectively reduces glioblastoma growth in vivo by affecting the structural integrity of tumor vasculature

3-Hydroxiglutaric acid (3-OH-GA) is a disease-specific metabolite that accumulates in tissues and body fluids of patients with Glutaric aciduria type I (GAI) and has been associated with vascular abnormalities in these kindreds. Here, we demonstrate that 3-OH-GA also affects the integrity of tumor vessels leading to tumor growth inhibition in a subcutaneous model of human glioblastoma multiforme (GBM). This effect correlated with a marked decrease of VE-Cadherin expression in endothelium of 3-OH-GA-treated tumors. Furthermore, in vitro observations indicated also a direct effect of 3-OH-GA in glioma cells that showed defective mitosis and significant proliferation inhibition. In summary, the GAI-specific metabolite 3-OH-GA significantly inhibited growth of GBM xenografts by affecting the structural integrity of tumor blood vessels and in addition by causing defective mitosis and proliferation inhibition of tumor cells.     

The role of basic fibroblast growth factor in glioblastoma multiforme and glioblastoma stem cells and in their in vitro culture

Glioblastoma multiforme (GBM) is the most malignant form of central nervous system tumor, and current therapies are largely ineffective at treating the cancer. Developing a more complete understanding of the mechanisms controlling the tumor is important in order to explore new possible treatment options. It is speculated that the presence of glioblastoma stem or stem-like cells (GSCs), a rare type of pluripotent cancer cell that possesses the ability to self-renew and generate tumors, could be an important factor contributing to the resistance to treatment and deadliness of the cancer. A comprehensive knowledge of the mechanisms controlling the expression and properties of GSCs is currently lacking, and one promising area for further exploration is in the influence of basic fibroblast growth factor (FGF-2) on GSCs. Recent studies reveal that FGF-2 plays a significant part in regulating GBM, and the growth factor is commonly included as a supplement in media used to culture GSCs in vitro. However, the particular role that FGF-2 plays in GSCs has not been as extensively explored. Therefore, understanding how FGF-2 is involved in GSCs and in GBMs could be an important step towards a more complete comprehension of the managing the disease. In this review, we look at the structure, signaling pathways, and specific role of FGF-2 in GBM and GSCs. In addition, we explore the use of FGF-2 in cell culture and using its synthetic analogs as a potential alternative to the growth factor in culture medium.     

In vivo glioblastoma growth is reduced by apyrase activity in a rat glioma model

Background  

ATP is an important signalling molecule in the peripheral and central nervous system. Both glioma growth and tumor resection induces cell death, thus liberating nucleotides to the extracellular medium. Nucleotides are hydrolyzed very slowly by gliomas when compared with astrocytes and induce neuronal cell death and glioma proliferation. The objective of the present study was to test the involvement of extracellular ATP in glioblastoma growth in a rat glioma model.     

Marchantin C,a novel microtubule inhibitor from liverwort with anti-tumor activity both in vivo and in vitro

Microtubules are long-standing targets in cancer chemotherapy. Previously, we reported that marchantin C triggers apoptosis of human tumor cells. We show here that marchantin C induced cell cycle arrest at G₂/M phase in A172 and HeLa cells. In addition, marchantin C decreased the quantity of microtubules in a time- and dose-dependent manner in these cells. Exposure of purified bovine brain tubulin to marchantin C inhibited polymerization of gross tubulin in vitro. Moreover, marchantin C potently suppressed the growth of human cervical carcinoma xenografts in nude mice. Marchantin C-treated xenografts showed decreased microtubules, Bcl-2 and increased cyclin B1, Bax, caspase-3, indicating that marchantin C possess the same ability to induce microtubules depolymerization and tumor cell apoptosis in tumor-bearing mice as in vitro. In conclusion, marchantin C is a novel microtubule inhibitor that induces mitotic arrest of tumor cells and suppresses tumor cell growth, exhibiting promising antitumor therapeutic potential.     

Therapeutic targeting of the mitotic spindle checkpoint through nanoparticle-mediated siRNA delivery inhibits tumor growth in vivo

The mitotic spindle checkpoint is a key signaling pathway that ensures proper chromosome segregation and was suggested as a novel target for anti-cancer treatment. Here, we explore a nanoparticle-based RNAi approach targeting the key spindle checkpoint gene MAD2 to investigate the suitability of the spindle checkpoint as a therapeutic target in vitro and in vivo. Repression of MAD2 causes severe chromosome missegregation in colon carcinoma cells associated with induction of apoptosis. Systemic administration of siRNA nanoparticles in nude mice results in reduced growth of xenograft tumors suggesting that inhibition of the spindle checkpoint represents a promising new concept for cancer therapy.     

Gold(III) porphyrin 1a inhibited nasopharyngeal carcinoma metastasis in vivo and inhibited cell migration and invasion in vitro

A physiologically stable gold compound, gold(III) meso-tetraphenylporphyrin (gold-1a), has been shown to be effective in inducing apoptosis and prolonging the survival of hepatocellular carcinoma (HCC)-bearing rats as well as inhibiting the tumor growth of mice bearing nasopharyngeal carcinoma (NPC), neuroblastoma and colon carcinoma. In this study, we showed that gold-1a prolonged the survival of NPC metastasis-bearing mice and inhibited intrahepatic and lung metastasis. Histologically, gold-1a markedly reduced tumor microvessel formation. Consistently, in in vitro studies, gold-1a inhibited migration and invasion of C666-1 human NPC cells. The data strongly support the use of gold(III) compounds to treat cancer metastasis.     

Structure-based discovery of a small non-peptidic Neuropilins antagonist exerting in vitro and in vivo anti-tumor activity on breast cancer model

Neuropilin-1/-2 (+33 NRPs), VEGF-A₁₆₅ co-receptors_, are over-expressed during cancer progression. Thus, NRPs targeted drug development is challenged using a multistep in silico/in vitro screening procedure. The first fully non-peptidic VEGF-A₁₆₅/NRPs protein–protein interaction antagonist (IC₅₀ = 34 μM) without effect on pro-angiogenic kinases has been identified (compound-1). This hit showed breast cancer cells anti-proliferative activity (IC₅₀ = 0.60 μM). Compound-1 treated NOG-xenografted mice significantly exerted tumor growth inhibition, which is correlated with Ki-67^low expression and apoptosis. Furthermore, CD31⁺/CD34⁺ vessels are reduced in accordance with HUVEC-tube formation inhibition (IC₅₀ = 0.20 μM). Taking together, compound-1 is the first fully organic inhibitor targeting NRPs.     

Composition of PLGA and PEI/DNA nanoparticles improves ultrasound-mediated gene delivery in solid tumors in vivo

The goal of this study was to enhance gene delivery and tumor cell transfection in vivo by using a combination of ultrasonication with complex nanoparticles consisting of two types of nanoparticles: PEI/DNA β-gal plasmid with highly positive zeta-potential and air-filled poly (lactic-co-glycolic acid) (PLGA) particles (with negative zeta-potential) manufactured in our laboratory. The PLGA/PEI/DNA nanoparticles were a colloid with positive zeta-potential and injected i.v. in nude mice with DU145 human prostate tumors. We found that the combination of PLGA/PEI/DNA nanoparticles with ultrasonication substantially enhanced tumor cell transfection in vivo. The overexpression of β-gal gene was evaluated histochemically and by Western blot analysis. At least an 8-fold increase of the cell transfection efficacy was obtained in irradiated tumors compared to non-irradiated controls, while little to no cell death was produced by ultrasonication.     

Moscatilin,a bibenzyl derivative from the India orchid Dendrobrium loddigesii, suppresses tumor angiogenesis and growth in vitro and in vivo

Attacking angiogenesis is considered an effective strategy for controls the expansion and metastasis of tumors and other related-diseases. The aim of this study was to assess the effects of moscatilin, a bibenzyl derivative, on VEGF and bFGF-induced angiogenesis in cultured human umbilical vein endothelial cells (HUVECs) in vitro and in vivo. Moscatilin significantly inhibited growth of lung cancer cell line A549 (NSCLC) and suppressed growth factor-induced neovascularization. In addition, VEGF- and bFGF-induced cell proliferation, migration, and tube formation of HUVECs was markedly inhibited by moscatilin. Western blotting analysis of cell signaling molecules indicated that moscatilin inhibited ERK1/2, Akt, and eNOS signaling pathways in HUVECs. These results suggest that inhibition of angiogenesis by moscatilin may be a major mechanism in cancer therapy.     

Local bystander effect induces dormancy in human medullary thyroid carcinoma model in vivo

The extent of local bystander effect induced by fusion yeast cytosine deaminase::uracil phosphoribosyltransferase (yCD) in combination with 5-fluorocytosine (5FC) was evaluated in xenogeneic model of human medullary thyroid carcinoma (MTC). This approach to gene-directed enzyme/prodrug therapy (GDEPT) induces strong bystander cytotoxicity. Effector yCD-TT mixed with target EGFP-TT cells in a ratio 2:9 could achieve significant tumor regression and 14-fold decrease in serum marker calcitonin upon 5FC administration. Histopathological analysis unraveled that antitumor effect resulted in tumor dormancy and proliferation arrest of remaining tumor cell clusters in vivo. yCD/5FC combination represents another GDEPT approach to achieve tumor growth control in MTC.     

NAD depletion by APO866 in combination with radiation in a prostate cancer model,results from an in vitro and in vivo study

Background

APO866 is a highly specific inhibitor of nicotinamide phosphoribosyltransferase (NAMPT), inhibition of which reduces cellular NAD⁺ levels. In this study we addressed the potential of NAD⁺ depletion as an anti-cancer strategy and assessed the combination with radiation.

Methods

The anticipated radiosensitizing property of APO866 was investigated in prostate cancer cell lines PC3 and LNCaP in vitro and in PC3 xenografts in vivo.

Results

We show that APO866 treatment leads to NAD⁺ depletion. Combination experiments with radiation lead to a substantial decrease in clonogenic cell survival in PC3 and LNCaP cells.In PC3 xenografts, treatment with APO866 resulted in reduced intratumoral NAD⁺ levels and induced significant tumor growth delay. Combined treatment of APO866 and fractionated radiation was more effective than the single modalities. Compared with untreated tumors, APO866 and radiation alone resulted in tumor growth delays of 14 days and 33 days, respectively, whereas the combination showed a significantly increased tumor growth delay of 65 days.

Conclusions

Our studies show that APO866-induced NAD⁺ depletion enhances radiation responses in tumor cell survival in prostate cancer. However, the in vitro data do not reveal a solid cellular mechanism to exploit further clinical development at this moment.     

CR13626: a novel oral brain penetrant tyrosine kinase inhibitor that reduces tumor growth and prolongs survival in a mouse model of glioblastoma

Glioblastoma multiforme (GBM) is the most malignant primary brain cancer. Despite aggressive treatments currently there is no cure for GBM. Many challenges should be considered for the development of new therapeutical agents for glioblastoma, including appropriate target selectivity and pharmacokinetics. Several mutations and alterations of key cellular pathways including tyrosine kinases (TKs) are involved in malignant transformation and tumor progression. Thus, the targeting of multiple pathways and the development of innovative combination drug regimens is expected to yield improved therapies. Moreover, the abilities to cross the blood-brain barrier (BBB) reaching effective concentrations in brain and to remain into this tissue avoiding the effects of efflux transporters are also critical issues in the development of new therapeutics for GBM. CR13626 is a novel brain penetrant small molecule able to potently inhibit in vitro the activity of EGFR, VEGFR2 (aka KDR), Fyn, Yes, Lck, HGK (aka MAP4K4) and RET kinases relevant for GBM development. CR13626 shows good oral bioavailability (72%) and relevant brain penetration (brain/plasma ratio of 1.4). In an orthotopic xenograft glioblastoma mouse model, oral treatment with CR13626 results in a time-dependent reduction of tumor growth, leading to a significant increase of animal survival. The unique properties of CR13626 warrant its further investigation as a potential new drug candidate in glioblastoma.     

Vanadium in the detection,prevention and treatment of cancer: The in vivo evidence

Vanadium, a dietary micronutrient, is yet to be established as an essential part of the human diet. Over the past century, several biological effects of vanadium, such as insulin-mimetic action as well as amelioration of hyperlipidemia and hypertension, have been discovered. This transition element is known to influence a battery of enzymatic systems, namely phosphatases, ATPases, peroxidases, ribonucleases, protein kinases and oxidoreductases. Multiple biochemical and molecular actions of vanadium have been implicated in its inhibitory effects on various tumor cells of human origin. Successful in vitro studies over the past few decades have advanced the anticancer research on vanadium into the preclinical stage. Vanadium in several animal cancer models provides protection against all stages of carcinogenesis – initiation, promotion, and progression. This review focuses on the current advances in cancer prevention and treatment as well as early detection by vanadium compounds in preclinical animal models while pointing to possible mechanisms of such diverse beneficial effects. Clinical pharmacokinetic and potential toxicity studies on vanadium are also highlighted in this review. Supporting and challenging evidence as well as future directions of vanadium research exploring the possibility of using this dietary agent for detection, prevention and treatment of human cancers are critically discussed.     

Progression and metastasis in a transgenic mouse breast cancer model: Effects of exposure to in vivo hypoxia

Hypoxia is a predictor of poor patient survival in several cancers, including breast carcinomas. One possible mechanism is genomic instability induced by oxic stress. In this study we examined this possible mechanism by exposing an in vivo breast cancer model to hypoxia/reoxygenation. MMTV-Neu transgenic mice were exposed to cycling acute (AH) or chronic hypoxia (CH) before (early) or after (late) tumour detection to study effects of hypoxia on tumour initiation and progression, respectively. We observed no effect of the hypoxic exposures on times to first tumour detection, but we saw a trend of early AH-exposed mice to develop more tumours and macrometastases than CH-exposed mice. Unexpectedly, but consistent with these findings, we observed significantly reduced 8-oxo-dG lesions levels in the mammary tissue with the greatest difference observed between the air control (AC) and AH-exposed groups. In the late gassing group, there was a similar trend for reduced 8-oxo-dG lesion levels, but interestingly mice that developed macroscopic lung metastases demonstrated significantly increased levels of 8-oxo-dG lesions in their tumours relative to those that did not, irrespective of the gassing exposure. A trend for increased macrophage content was observed in tumours from mice exposed to acute hypoxia. Our results indicate that oxic stress induced by hypoxia/reoxygenation is unlikely to be a major factor driving tumour progression of established MMTV-Neu tumours but suggest that acute and chronic hypoxia may affect tumour incidence and metastasis when applied prior to tumour development.     

Repeated hepatocyte growth factor neutralizing antibody treatment leads to HGF/SF unresponsiveness in human glioblastoma multiforme cells

The purpose of this work is to seek putative markers for multi-targeted therapeutic treatment of human glioblastoma. We previously developed an anti-HGF neutralizing antibody cocktail Amix that inhibits human glioblastoma growth in mouse xenograft models. When these treated tumors were re-injected into nude mice and treatment with the neutralizing antibody cocktail plus heparin was repeated, the growth of the twice-treated tumors became HGF-independent, suggesting a possible switch in dominant signaling pathways. Microarray of the tumor cells revealed a number of genes elevated in the twice-treated tumor cells relative to untreated control tumors, including BAI1, CASP8, IL8, IGF1, TGFB1 and TNF. Our analyses provide a series of putative markers for additional evaluation in treating glioblastoma. Multi-targeted therapeutic approach might be a better solution for treating this disease.     

Xylocydine,a novel Cdk inhibitor,is an effective inducer of apoptosis in hepatocellular carcinoma cells in vitro and in vivo

Hepatocellular carcinoma (HCC) frequently includes abnormalities in cell cycle regulators, including up-regulated cyclin-dependent kinase (Cdks) activities due to loss or low expression of Cdk inhibitors. In this study, we show that xylocydine, a cyclin-dependent kinase (Cdk) specific inhibitor, is a good anti-cancer drug candidate for HCC treatment. Xylocydine (50 μM) selectively down-regulates the activity of Cdk1 and Cdk2, accompanied by significant cell growth inhibition in HCC cells. Xylocydine also strongly inhibits the activity of Cdk7 and Cdk9, in vitro as well as in cell cultures, that is temporally associated with apoptotic cell death in xylocydine-induced HCC cells. This is associated with inhibition of phosphorylation of RNA polymerase II at serine residues 5 and 2, which are targets of Cdk7 and Cdk9, respectively. The effects on apoptosis are concomitant with changes in the levels of anti-apoptotic proteins, Bcl-2, XIAP, and survivin, which are markedly down-regulated, and pro-apoptotic molecules, p53 and Bax, which are elevated in HCC cells after treatment with xylocydine. The up-regulated level of p53 was associated with increased stability of the protein, as levels of Ser15 and Ser392 phsophorylated p53 are similarly elevated in the inhibitor treated cells. We demonstrated that xylocydine can effectively suppress the growth of HCC xenografts in Balb/C-nude mice by preferentially inducing apoptosis in the xenografts, whereas the drug did not cause any apparent toxic effect on other tissues. Taken together, these data suggest that the novel Cdk inhibitor xylocydine is a good candidate for an anti-cancer drug for HCC therapy.     

Adenovirus vector-mediated Gli1 siRNA induces growth inhibition and apoptosis in human pancreatic cancer with Smo-dependent or Smo-independent Hh pathway activation in vitro and in vivo

Activation of Hedgehog (Hh) signaling pathway is a core molecular mechanism in pancreatic carcinogenesis. However, the inhibition of upstream Hh signals does not inhibit the growth of a subset of pancreatic cancer (PC). This study was to examine the effect of siRNA targeting Gli1, the downstream component of Hh pathway, on PC cells and to provide some insight into the underlying mechanisms. A Gli1siRNA-expressing adenovirus (Ad-U6-Gli1siRNA) was constructed, and its effect on PC cells was investigated in vitro and in vivo. Gli1 was expressed in 83.3% (20/24) PC tissues, whereas no expression was found in normal pancreatic ductal epithelium. Gli1 was expressed in SW1990 and CFPAC cells in which Smo was completely absent, as well as in PaTu8988, Panc-1 and BxPC-3 cells in which Smo was concomitantly present. Ad-U6-Gli1siRNA induced cell growth inhibition, strong G0/G1 cell cycle arrest and apoptosis in all five human PC cell lines. Meanwhile, Ad-U6-Gli1siRNA significantly suppressed the expression of Gli1, Ptch1 and two target genes, Cyclin D2 and Bcl-2, in all five lines. Furthermore, two tumor xenograft nude mice models were established by subcutaneously injecting Smo-positive Panc-1 cells or Smo-negative SW1990 cells. The in vivo experimental results demonstrated that Ad-U6-Gli1siRNA inhibited the growth of both Panc1-derived and SW1990-derived tumors and induced cell apoptosis. Our study indicates that Gli1-targeting siRNA could induce growth inhibition and apoptosis in PC through knockdown of Gli1 and its target genes; and this method may represent a more effective therapeutic strategy for PC with Smo-dependent or Smo-independent Hh pathway activation.     

Ganoderma tsugae extract inhibits expression of epidermal growth factor receptor and angiogenesis in human epidermoid carcinoma cells: In vitro and in vivo

We examined the anti-angiogenic effects of Ganoderma tsugae methanol extract (GTME) on human epidermoid carcinoma A-431 cells. Our data indicate that GTME inhibits the expression of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) in vitro and in vivo, and also inhibits the capillary tube formation of human umbilical vein endothelial cells (HUVECs). We also show that the suppression of VEGF expression by GTME can be restored by treatment with EGF. These results suggest that GTME inhibits VEGF expression via the suppression of EGFR expression, resulting in the downregulation of VEGF secretion from epidermoid carcinoma A-431 cells. These findings reveal a novel role for G. tsugae in inhibiting EGFR and VEGF expression, which are important for tumor angiogenesis and growth. Thus, GTME may provide a potential therapeutic approach for anti-tumor treatment.     

Blocking p38/ERK crosstalk affects colorectal cancer growth by inducing apoptosis in vitro and in preclinical mouse models

We recently demonstrated that p38α is required to maintain colorectal cancer (CRC) metabolism, as its inhibition leads to FoxO3A activation, autophagy, cell death, and tumor growth reduction both in vitro and in vivo. Here we show that inhibition of p38α is followed by TRAIL-mediated activation of caspase-8 and FoxO3A-dependent HER3 upregulation with consequent overactivation of the MEK-ERK1/2 survival pathway. p38α and MEK combined inhibition specifically induces apoptosis by enabling TRAIL signaling propagation through t-Bid and caspase-3, and fosters cell death in CRC cells and preclinical mouse models. Current MEK1-directed pharmacological strategies could thus be exploited, in combination with p38α inhibition, to develop new approaches for CRC treatment.     

替莫唑胺缓释微球局部植入治疗大鼠脑胶质瘤的疗效

目的：研究替莫唑胺缓释微球（temozolomide/PLGA microsphere, TMMS）局部植入对大鼠C6胶质瘤的治疗效果。方法：将C6大鼠胶质瘤细胞接种于鼠脑左侧尾状核,制备大鼠脑胶质瘤模型。分别用替莫唑胺（temozolomide, TM）口服及TMMS肿瘤局部植入治疗,观察大鼠的一般情况、生存期、肿瘤体积大小、病理学变化;免疫组织化学染色检测胶质瘤组织中增殖细胞核抗原（proliferadion cell nuclear antigen, PCNA）蛋白的表达;TUNEL法检测胶质瘤组织细胞的凋亡。结果：TMMS治疗大鼠的生存期较假手术组、空载体组、替莫唑胺口服组明显延长\[（31.2±6.21）d vs （20.7±4.83）、（19.2±6.23）、（24.7±6.31）d;P<0.05或P<0.01\]。MRI检查显示经TMMS治疗后脑内瘤灶体积较假手术组、空载体组、替莫唑胺口服组明显缩小\[（28.8±6.41）mm3 vs （56.4±6.92）、（58.2±5.36）、（46.7±7.28）mm3;P<0.05或P<0.01\];TMMS治疗后肿瘤细胞PCNA表达率较假手术组、空载体组、替莫唑胺口服组显著降低\[（20.2±4.33）% vs （63.2±5.91）%、（62.1±7.88）%、（41.7±6.71）%;P<001\],细胞凋亡率也明显增高\[（32.31±317）% vs （8.63±1.52）%、（9.25±2.31）%、（16.14±3.42）%;P<0.01\]。结论：TMMS局部植入治疗大鼠脑胶质瘤能显著抑制脑胶质瘤细胞增殖、诱导肿瘤细胞凋亡、延长大鼠生存期,具有潜在的临床应用价值。