fosbretabulin and Carcinoma--Hepatocellular

Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/Combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) have shown great potential in synergistic cancer therapy. However, it is still unclear how the nanoparticles' formula, such as injection dose, active agent ratio, and drug loading content, affects the side effects and in vivo efficacy of CB-NPs. In this study, a series of CB-NPs with different BLZ945/CA4 (B/C) ratios and drug loading contents were synthesized and evaluated on a hepatoma (H22) tumor-bearing mice model. The injection dose and B/C ratio were found to have a significant influence on the in vivo anticancer efficacy. The CB-NPs 20 with B/C weight ratio of 0.45/1, and total drug loading content (B + C) of 20.7 wt%, showed the highest potential for clinical application. Systematic pharmacokinetics, biodistribution, and in vivo efficacy evaluation for CB-NPs 20 have been finished, which may provide significant instruction for medicine screening and clinical application.

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Glutamic Acid; Mice; Mice, Inbred BALB C; Nanoparticles; Polyethylene Glycols; Tissue Distribution

Tumor angiogenesis plays a crucial role in tumor development, and recent efforts have been focused on combining proapoptotic and antiangiogenic activities to enhance antitumor therapy.. In this study, galactose-modified liposomes (Gal-LPs) were prepared for co-delivery of doxorubicin (DOX) and combretastatin A4 phosphate (CA4P). The co-cultured system composed of BEL-7402 and human umbilical vein endothelial cells (HUVEC) cells was established to effectively evaluate in vitro anti-tumor activity through cell viability and cell migration assay. Furthermore, both in vivo bio-distribution and anti-hepatoma effect of DOX&CA4P/Gal-LPs were investigated on H22 tumor cell-bearing mice.. The results showed that DOX&CA4P/Gal-LPs were spherical with a mean particle size of 143 nm, and could readily be taken up by BEL-7402 cells. Compared with a mixture of free DOX and CA4P, the DOX&CA4P/Gal-LPs were more effective in inhibiting cell migration and exhibited stronger cytotoxicity against BEL-7402 cells alone or a co-cultured system. The in vitro studies showed that the co-cultured system was a more effective model to evaluate the anti-tumor activity of combination therapy. Moreover, DOX&CA4P/Gal-LPs exhibited a greater anti-hepatoma effect than other drug formulations, indicating that Gal-LPs could promote drug accumulation in the tumor region and improve the anti-tumor activity.. Gal-LPs co-loaded with chemotherapeutic and antiangiogenic drugs are a promising strategy for anti-hepatoma therapy.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Cell Survival; Doxorubicin; Drug Compounding; Galactose; Human Umbilical Vein Endothelial Cells; Humans; Liposomes; Liver Neoplasms; Mice; Particle Size; Stilbenes

Combretastatin A4 phosphate (CA4P), a vascular disrupting agent (VDA), can cause rapid tumour vessel occlusion. Subsequently, extensive necrosis is discovered in the tumour center, which induces widespread hypoxia and the rise of the α subunit of hypoxia-inducible factor-1 (HIF-1α). The aim of this study was to evaluate the inhibition of hepatocellular carcinoma growth by combining CA4P with HIF-1 α inhibitor and investigate the mechanism of this combination.. Ginsenoside Rd (Rd) was used in combination with CA4P to estimate the inhibition effect in HepG2 cells and HepG2 xenograft mouse model. The efficacy of anti-tumour was evaluated by tumour growth curve. The protein expression of HIF-1α and PI3K/AKT/mTOR signalling pathway were analysed by western blot.. Combination of CA4P and Rd inhibited HepG2 cell proliferation and induced apoptosis in vivo and in vitro. It also increased the necrotic area of the tumour and delayed the tumour growth. Moreover, Rd down-regulated HIF-1α protein expression by inhibiting PI3K/AKT/mTOR signalling pathway.. Combination of CA4P and Rd had synergistic anti-tumour effects. The mechanism may be related to the inhibition of HIF-1α by PI3K/AKT/mTOR signalling pathway. This strategy provides a new thought for the combinative therapy of VDAs.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carcinoma, Hepatocellular; Drug Synergism; Ginsenosides; Hep G2 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Signal Transduction; Stilbenes; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

According to data estimated by the WHO, primary liver cancer is currently the fourth most common malignant tumor and the second leading cause of death around the world. Hepatocellular carcinoma (HCC) is one of the most common primary liver malignancies, so effective therapy is highly desired for HCC.. In this study, the use of poly(L-Aspartic acid)-poly(ethylene glycol)/combretastatin A4 (CA4-NPs) was aimed to significantly disrupt new blood vessels in tumor tissues for targeted hepatic tumor therapy. Here, PEG-b-PAsp-g-CA4 showed significantly prolonged retention in plasma and tumor tissue. Most importantly, CA4-NPs were mainly distributed at the tumor site because of the triple target effects-enhanced permeability and retention (EPR) effect, acid-sensitive (pH = 5.5) effect to the tumor microenvironment (TME), and good selectivity of CA4 for central tumor blood vessel. Considering that CA4-NPs might induce severe hypoxic conditions resulting in high expression of HIF-1α in tumor tissues, which could induce the overexpression of PD-L1, herein we also used a programmed death-ligand 1 antibody (aPD-L1) to prevent immunosuppression. This way of complementary combination is able to achieve an ideal treatment effect in tumor site where CA4-NPs and aPD-L1 could respond to the inner area and peripheral area, respectively. As a result, a significant decrease in tumor volume and weight was observed in the combination group of CA4-NPs plus aPD-L1 compared with CA4-NPs or aPD-L1 monotherapy in subcutaneous Hepa1-6 hepatic tumor models.. We presented a new idea that co-administration of CA4-NPs and aPD-L1 possessed notable anti-tumor efficacy for HCC treatment.

Topics: Animals; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; B7-H1 Antigen; Carcinoma, Hepatocellular; Disease Models, Animal; Drug Synergism; Female; Humans; Liver Neoplasms; Mice; Mice, Inbred C57BL; Nanoparticles; Polyethylene Glycols; Stilbenes; Tumor Microenvironment

Tumor angiogenesis has been proven to potentiate tumor growth and metastasis; therefore, the strategies targeting tumor-related angiogenesis have great potentials in antitumor therapy.. Here, the GA&Gal dual-ligand-modified liposomes co-loaded with curcumin and combretastatin A-4 phosphate (CUCA/GA&Gal-Lip) were prepared and characterized. A novel "BEL-7402+HUVEC" co-cultured cell model was established to mimic tumor microenvironment. The cytotoxicity and migration assays were performed against the novel co-cultured model. Angiogenesis ability was evaluated by tube formation test, and in vivo metastatic ability was evaluated by lung metastasis test.. The result demonstrated that dual-ligand-modified liposomes showed greater inhibition of tumor angiogenesis and metastasis in comparison with other combined groups. Significantly, the mechanism analysis revealed that curcumin and combretastatin A-4 phosphate could inhibit tumor angiogenesis and metastasis via down-regulation of VEGF and VEGFR2 expression, respectively, and that GA&Gal-Lip could improve antitumor effect by GA/Gal-mediated active-targeting delivery.. CUCA/GA&Gal-Lip hold great potentials in hepatoma-targeting delivery of antitumor drugs and can achieve anti-angiogenic and anti-metastatic effects by simultaneously blocking VEGF/VEGFR2 signal pathway, therefore exhibiting superior anti-hepatoma efficacy.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Cell Line, Tumor; Curcumin; Drug Liberation; Gene Expression Regulation, Neoplastic; Human Umbilical Vein Endothelial Cells; Humans; Ligands; Liposomes; Liver Neoplasms; Lung Neoplasms; Mice, Inbred BALB C; Neovascularization, Pathologic; Stilbenes; Xenograft Model Antitumor Assays

Hepatocellular carcinoma (HCC) is a tough opponent. HCC contributes to 14.8% of all cancer mortality in Egypt. There are many choices for management of HCC; however tumor relapse has been reported in animal and clinical studies. This study was conducted to investigate the impact of low dose γ-irradiation (LDR) and combretastatin A-4 disodium phosphate (CA-4DP) on HCC recurrence. HCC was induced in male Wistar albino rats by oral administration of N-nitrosodiethylamine (NDEA) for 17 weeks. We evaluated the expression of the endothelial cell marker (CD31) by immunostaining. Expression of Rho Associated Coiled-Coil Containing Protein Kinase 1(ROCK1) and Vascular endothelial growth factor (VEGF) expression was assessed by real-time PCR after (6, 24 and 48 h). Our results showed that expression of CD31 and gene expression of ROCK1 and VEGF was significantly repressed at all-time intervals by combination therapy ofLDR and CA-4DP as compared with untreated NDEA/HCC group and NDEA/HCC groups treated with either LDR or CA-4DP alone, (P < 0.05). Our study demonstrated the additive effect of LDR in combination with CA-4DP in suppression of HCC.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Chemoradiotherapy; Combined Modality Therapy; Diethylnitrosamine; Down-Regulation; Egypt; Gamma Rays; Gene Expression Regulation, Neoplastic; Liver Neoplasms; Male; Platelet Endothelial Cell Adhesion Molecule-1; Rats; Rats, Wistar; rho-Associated Kinases; Stilbenes; Treatment Outcome; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Death; Cell Survival; Human Umbilical Vein Endothelial Cells; Humans; Ki-67 Antigen; Liver Neoplasms; Male; Mice, Inbred BALB C; Nanoparticles; Platelet Endothelial Cell Adhesion Molecule-1; Sorafenib; Stilbenes; Treatment Outcome; Vascular Endothelial Growth Factor A

To better inform the next clinical trials of vascular disrupting agent combretastatin-A4-phosphate (CA4P) in patients with hepatic malignancies, this preclinical study aimed at evaluating CA4P therapeutic efficacy in rats with primary hepatocellular carcinomas (HCCs) of a full spectrum of differentiation and vascularity by magnetic resonance imaging (MRI), microangiography and histopathology. Ninety-six HCCs were raised in 25 rats by diethylnitrosamine gavage. Tumor growth was monitored by T2-/T1-weighted-MRI (T2WI, T1WI) using a 3.0 T scanner. Early vascular response and later intratumoral necrosis were detected by dynamic-contrast-enhanced (DCE) MRI and diffusion-weighted-imaging (DWI) before, 1 and 12 hr after CA4P iv-administration. In vivo MRI-findings were validated by postmortem-techniques. Multi-parametric MRI revealed rapid CA4P-induced tumor vascular shutdown within 1 hr, followed by variable intratumoral necrosis at 12 hr. Tumor volumes decreased by 10% at 1 hr (p < 0.05), but resumed at 12 hr. Correlations of semi-quantitative DCE parameter initial-area-under-the-gadolinium-curve (IAUGC30) with histopathology proved partial vascular closure and compensational reopening (p < 0.05). The higher grades of vascularity prevented those residual tumor tissues from CA4P-caused ischemic necrosis. By histopathology using a 4-scale cellular-differentiation criteria and a 4-grade tumor-vascularity classification, percentage of CA4P-induced necrosis negatively correlated with HCC differentiation (r = -0.404, p < 0.001) and tumor vascularity (r = -0.370, p < 0.001). Ordinal-logistic-regression helped to predict early tumor responses to CA4P in terms of tumoral differentiation and vascularity. Our study demonstrated that CA4P could induce vascular shutdown in primary HCCs within 1 hr, resulting in various degrees of tumor necrosis at 12 hr. MRI as a real-time imaging biomarker may help to define tumor vascularity and differentiation and further to predict CA4P therapeutic outcomes.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Contrast Media; Humans; Liver Neoplasms; Magnetic Resonance Imaging; Male; Neovascularization, Pathologic; Rats; Rats, Sprague-Dawley; Stilbenes; Tumor Burden; Tumor Cells, Cultured

Stepwise pH-responsive nanoparticle system containing charge reversible pullulan-based (CAPL) shell and poly(β-amino ester) (PBAE)/poly(lactic-co-glycolic acid) (PLAG) core is designed to be used as carriers of paclitaxel (PTX) and combretastatin A4 (CA4) for combining antiangiogenesis and chemotherapy to treat hepatocellular carcinoma (HCC). CAPL-coated PBAE/PLGA (CAPL/PBAE/PLGA) nanoparticles displayed step-by-step responses to weakly acidic tumor microenvironment (pH ≈6.5) and endo/lysosome (pH ≈5.5) respectively through the cleavage of β-carboxylic amide bond in CAPL and the "proton-sponge" effect of PBAE, thus realized the efficient and orderly releases of CA4 and PTX. In human HCC HepG2 cells and human umbilical vein endothelial cells, CAPL/PBAE/PLGA nanoparticles significantly enhanced synergistic effects of PTX and CA4 on cell proliferation and cell migration. In HepG2 tumor-bearing mice, CAPL/PBAE/PLGA nanoparticles showed excellent tumor-targeting capability and remarkably increased inhibitory effects of PTX and CA4 on tumor growth and angiogenesis. In conclusion, this novel nanoparticle system is a promising candidate as carrier for drugs against HCC.

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Proliferation; Delayed-Action Preparations; Glucans; Hep G2 Cells; Human Umbilical Vein Endothelial Cells; Humans; Hydrogen-Ion Concentration; Lactic Acid; Liver; Liver Neoplasms; Mice; Mice, Nude; Nanoparticles; Paclitaxel; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Stilbenes

Purpose To determine if combretastatin A-4 phosphate disodium (CA4P) can enhance the tumor uptake of doxorubicin (Dox)-loaded, polyethylene glycol (PEG)-coated hollow gold nanospheres (HAuNS) mixed with ethiodized oil for improved photothermal ablation (PTA)-chemoembolization therapy (CET) of hepatocellular carcinoma (HCC) in rats. Materials and Methods Animal experiments were approved by the institutional animal care and use committee and performed from February 2014 to April 2015. Male Sprague-Dawley rats (n = 45; age, 12 weeks) were inoculated with N1S1 HCC cells in the liver, and 8 days later, were randomly divided into two groups of 10 rats. Group 1 rats received intrahepatic arterial injection of PEG-HAuNS and ethiodized oil alone; group 2 received pretreatment with CA4P and injection of PEG-HAuNS and ethiodized oil 5 minutes later. The gold content of tumor and liver tissue at 1 hour or 24 hours after injection was quantified by using neutron activation analysis (n = 5 per time point). Five rats received pretreatment CA4P, PEG-copper 64-HAuNS, and ethiodized oil and underwent micro-positron emission tomography (PET)/computed tomography (CT). In a separate study, three groups of six rats with HCC were injected with saline solution (control group); CA4P, Dox-loaded PEG-coated HAuNS (Dox@PEG-HAuNS), and ethiodized oil (CET group); or CA4P, Dox@PEG-HAuNS, ethiodized oil, and near-infrared irradiation (PTA-CET group). Temperature was recorded during laser irradiation. Findings were verified at postmortem histopathologic and/or autoradiographic examination. Wilcoxon rank-sum test and Pearson correlation analyses were performed. Results PEG-HAuNS uptake in CA4P-pretreated HCC tumors was significantly higher than that in non-CA4P-pretreated tumors at both 1 hour (P < .03) and 24 hours (P < .01). Mean ± standard deviation of tumor-to-liver PEG-HAuNS uptake ratios at 1 hour and 24 hours, respectively, were 5.63 ± 3.09 and 1.68 ± 0.77 in the CA4P-treated group and 1.29 ± 2.40 and 0.14 ± 0.11 in the non-CA4P-treated group. Micro-PET/CT allowed clear delineation of tumors, enabling quantitative imaging analysis. Laser irradiation increased temperature to 60°C and 43°C in the tumor and adjacent liver, respectively. Mean HCC tumor volumes 10 days after therapy were 1.68 cm

Topics: Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Chemoembolization, Therapeutic; Disease Models, Animal; Doxorubicin; Drug Carriers; Ethiodized Oil; Gold; Hyperthermia, Induced; Liver Neoplasms; Male; Nanospheres; Polyethylene Glycols; Positron Emission Tomography Computed Tomography; Random Allocation; Rats; Rats, Sprague-Dawley; Stilbenes

The aim of the present study is to verify the trapping effect of combretastatin A-4-phosphate (CA4P) on small molecular drugs in rodent tumors. Mice with H22 hepatocarcinoma were randomized into groups A and B. Magnetic resonance imaging (MRI) of T1WI, T2WI, and DWI was performed as baseline. Mice in group A were injected with Gd-DTPA and PBS. Mice in group B were injected with Gd-DTPA and CA4P. All mice undergo CE-T1WI at 0 h, 3 h, 6 h, 12 h, and 24 h. Enhancing efficacy of the two groups on CE-T1WI was compared with the signal-to-noise ratio (SNR) calculated. Concentrations of gadolinium measured by ICP-AES in the tumor were compared between groups. On the early CE-T1WI, tumors were equally enhanced in both groups. On the delayed CE-T1WI, the enhancing effect of group A was weaker than that of group B. The SNR and the concentration of gadolinium within the tumor of group A were lower than that of group B at 6 h, 12 h, and 24 h after administration. This study indicates that CA4P could improve the retention of Gd-DTPA in the tumor and MRI allowed dynamically monitoring trapping effects of CA4P on local retention of Gd-DTPA as a small molecular drug.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Contrast Media; Disease Models, Animal; Gadolinium DTPA; Liver Neoplasms; Magnetic Resonance Imaging; Male; Mice; Spectrophotometry, Atomic; Stilbenes; Time Factors; Tissue Distribution

A new class of compounds that incorporated the structural motif of the 1-(3',4',5'-trimethoxtbenzoyl)-3-arylamino-5-amino-1,2,4-triazole molecular skeleton was synthesized and evaluated for their antiproliferative activity in vitro, interactions with tubulin, and cell cycle effects. The most active agent, 3c, was evaluated for antitumor activity in vivo. Structure-activity relationships were elucidated with various substituents on the phenyl ring of the anilino moiety at the C-3 position of the 1,2,4-triazole ring. The best results for inhibition of cancer cell growth were obtained with the p-Me, m,p-diMe, and p-Et phenyl derivatives 3c, 3e, and 3f, respectively, and overall, these compounds were more or less as active as CA-4. Their vascular disrupting activity was evaluated in HUVEC cells, with compound 3c showing activity comparable with that of CA-4. Compound 3c almost eliminated the growth of syngeneic hepatocellular carcinoma in Balb/c mice, suggesting that 3c could be a new antimitotic agent with clinical potential.

Topics: Angiogenesis Inhibitors; Aniline Compounds; Animals; Antimitotic Agents; Antineoplastic Agents; Apoptosis; Carcinoma, Hepatocellular; Cell Cycle; Cell Proliferation; Colchicine; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Human Umbilical Vein Endothelial Cells; Humans; Liver Neoplasms; Mice, Inbred BALB C; Models, Molecular; Neoplasm Transplantation; Neoplastic Stem Cells; Protein Binding; Stereoisomerism; Structure-Activity Relationship; Triazines; Triazoles; Tubulin; Tubulin Modulators

5-(3-Hydroxy-4-methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-3H-1,2-dithiol-3-one (COH-203) is a novel synthesized analogue of combretastatin A-4 that can be classified as a microtubule inhibitor. In this study, we evaluated the anti-hepatoma effect of COH-203 in vitro and in vivo and explored the underlying molecular mechanisms. COH-203 was shown to be more effective in inhibiting the proliferation of liver cancer cells compared with normal liver cells. COH-203 also displayed potent anti-tumor activity in a hepatocellular carcinoma xenograft model without significant toxicity. Mechanistic studies demonstrated that treatment with COH-203 induced mitotic arrest by inhibiting tubulin polymerization in BEL-7402 liver cancer cells. Long-term COH-203 treatment in BEL-7402 cells led to mitotic slippage followed by senescence via the p14(Arf)-p53-p21 and p16(INK4α)-Rb pathways. Furthermore, suppression of p53 via pifithrin-α (p53 inhibitor) and p53-siRNA attenuated COH-203-induced senescence in BEL-7402 cells, suggesting that COH-203 induced senescence p53-dependently. In conclusion, we report for the first time that COH-203, one compound in the combretastatin family, promotes anti-proliferative activity through the induction of p-53 dependent senescence. Our findings will provide a molecular rationale for the development of COH-203 as a promising anti-tumor agent.

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cellular Senescence; Heterocyclic Compounds, 1-Ring; Humans; Liver; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Microtubules; RNA, Small Interfering; Stilbenes; Tubulin; Tubulin Modulators; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays

This study designs a pH-sensitive nanoparticle carrier of methotrexate (MTX) and combretastatin A4 (CA4) based on pullulan for the combination therapy against hepatocellular carcinoma (HCC). Briefly, N-urocanyl pullulan (URPA) with the degree of substitution (DS) of 5.2% was synthesized and then conjugated with MTX to form MTX-URPA, in which MTX content was 17.8%. MTX-URPA nanoparticles prepared by the dialysis method had spherical shape and the mean size of 187.1 nm, and showed high affinity for HepG2 cells. CA4 was successfully loaded into MTX-URPA nanoparticles and exhibited pH-sensitive in vitro release property. After intravenous injection to PLC/PRF/5-bearing nude mice, CA4 loaded MTX-URPA (CA4/MTX-URPA) nanoparticles achieved the enhanced antitumor and anti-angiogenic effects, the prolonged circulation time in blood, and the increased distributions both in the liver and the tumor. In conclusion, this drug carrier system has significant liver-targeting property and exhibits advantages for the combination therapy against hepatocellular carcinoma.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Hepatocellular; Delayed-Action Preparations; Glucans; Hep G2 Cells; Humans; Hydrogen-Ion Concentration; Liver; Liver Neoplasms; Methotrexate; Mice; Mice, Inbred BALB C; Mice, Nude; Models, Molecular; Nanoparticles; Stilbenes

The present data showed that a novel synthesized compound, N-acetyl-N-(4-(4-methoxyphenyl-3-(3,4,5-trimethoxyphenyl)isoxazol-5-yl)acetamide (XN05), exhibited potent antitumor activity against various cancer cells in vitro. XN05-treatment in human hepatocellular carcinoma cells resulted in the accumulation of G2/M phase cells and finally induced apoptosis assessed by flow cytometry analysis. Western blot and immunofluorescence experiments indicated that XN05 depolymerized microtubules similar to the effect of combretastatin-A4. In addition, XN05-treatment influenced the expression of cell cycle and apoptosis related proteins in BEL-7402 cells, which was associated with the appearance of phosphorylated Bcl-2. Taken together, all the data demonstrated that XN05 exhibited its antitumor activity through disrupting the microtubule assembly, causing cell cycle arrest and consequently inducing apoptosis in BEL-7402 cells. Therefore, the novel compound XN05 is a promising microtubule inhibitor that has great potentials for therapeutic treatment of various malignancies.

Topics: Acetamides; Apoptosis; Carcinoma, Hepatocellular; Caspases; Cell Cycle; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Enzyme Activation; Humans; Inhibitory Concentration 50; Isoxazoles; Liver Neoplasms; Microtubules; Phosphorylation; Protein Multimerization; Proto-Oncogene Proteins c-bcl-2; Stilbenes; Time Factors; Tubulin; Tubulin Modulators

Combretastatin A4 (CA4) is a novel vascular disrupting agent that has promising clinical efficacy because of its ability to inhibit microtubule assembly and subsequently disrupt tumor blood flow. In this study, we demonstrate that mitogen-activated protein kinases (MAPKs) are critically involved in the cytotoxicity of CA4. CA4 stimulates both extracellular signal-regulated kinases (ERK1/2) and p38 MAPK in the BEL-7402 hepatocellular carcinoma cell line in a time- and dose-dependent manner. This stimulation is a result of CA4-induced microtubule disassembly, which is a reversible process. Reversibility of microtubule disassembly is evidenced by the ability of disassembled microtubules to reassemble just a few hours after CA4 treatment. p38 MAPK, but not ERK1/2, contributes to this microtubule reassembly following CA4 exposure, and only inhibition of p38 MAPK, but not ERK1/2, synergistically enhances CA4-induced G(2)/M cell cycle arrest. Consistent with this, p38 MAPK inhibitors such as SB203580 and SB202190 also synergistically enhance the cytotoxicity of CA4 in cells where p38 MAPK is activated by CA4. This enhancement appears to be specific for CA4 because the cytotoxicity of other microtubule-targeted agents such as paclitaxel, vinorelbine and colchicine was not affected by p38 MAPK inhibitors. These data indicate that p38 MAPK is a potential anticancer target and that the combination of CA4 with p38 MAPK inhibitors may be a novel and promising strategy for cancer therapy.

Topics: Angiogenesis Inhibitors; Antineoplastic Agents, Phytogenic; Blotting, Western; Carcinoma, Hepatocellular; Cell Line, Tumor; Dose-Response Relationship, Drug; Enzyme Inhibitors; Female; Fluorescent Antibody Technique; Humans; Imidazoles; Liver Neoplasms; Male; Microtubules; Ovarian Neoplasms; p38 Mitogen-Activated Protein Kinases; Pyridines; Stilbenes; Time Factors

Two series of carbazole sulfonamides related to Combretastatin A4 (1) were synthesized and evaluated for antiproliferative activity. Thirteen of the 26 new sulfonamides exhibited IC(50) values of <1 muM against CEM leukemia cells. Five compounds were evaluated against a panel of eight human tumor cell lines. 9-Ethyl-N-(3,4,5-trimethoxyphenyl)-carbazole-3-sulfonamide (11a) showed significant antitumor activity in two human xenograft models (MCF-7 and Bel-7402). Preliminary studies with 11a showed that the mode of action involves arrest of M-phase cell cycle and induction of apoptosis by increasing expression of p53 and promoting bcl-2 phosphorylation. Unexpectedly, 11a only weakly inhibits tubulin polymerization, which suggests that the mode of action of 11a differs from 1 and involves an unidentified target(s). Also, the SAR information gleaned from ring A-substituted analogues varies significantly from that of 1. Carbazole sulfonamides are a novel promising class of antimitotic agents with clinical development potential.

Topics: Animals; Antimitotic Agents; Apoptosis; Breast Neoplasms; Carbazoles; Carcinoma, Hepatocellular; Cell Division; Cell Line, Tumor; Drug Screening Assays, Antitumor; Female; Humans; Liver Neoplasms; Mice; Mice, Nude; Neoplasm Transplantation; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Structure-Activity Relationship; Sulfonamides; Transplantation, Heterologous; Tumor Suppressor Protein p53