fosbretabulin and Colonic-Neoplasms

Chimeric antigen receptor (CAR) T cell therapy remains relatively ineffective against solid tumors due to inadequate infiltration and in vivo expansion of CAR-T cells. Unlike hematological malignancies, solid tumors have vascular barriers that hinder CAR-T cells from reaching the tumor site. Here, we demonstrated that combretastatin A-4 phosphate (CA4P), a vascular disrupting agent (VDA), can significantly improve the infiltration ability of CAR-T cells in solid tumors as evidenced by elevated levels of IFN-γ. Moreover, combined treatment with CA4P and CAR-T cells greatly increased the therapeutic efficiency of the CAR-T cells in subcutaneous ovarian cancer mouse xenograft models and patient-derived xenograft (PDX) models of colon and ovarian carcinoma. Our findings highlight CA4P as an effective antitumor agent candidate for combination with CAR-T cells in clinical applications to treat solid tumors.

Topics: A549 Cells; Animals; Antineoplastic Agents, Phytogenic; Colonic Neoplasms; Female; HCT116 Cells; HEK293 Cells; Humans; Immunotherapy, Adoptive; Mice; Mice, Inbred NOD; Mice, SCID; Ovarian Neoplasms; Receptors, Chimeric Antigen; Stilbenes; Treatment Outcome; Tumor Burden; Xenograft Model Antitumor Assays

The colchicine site inhibitors (CSIs) displayed both antimitotic and vascular disrupting activities, therefore are promising potential antitumor agents. In this study, a series 1-phenyl-4,5-dihydro-2H-benzo[e]indazoles were found as new CSIs of which the bioactive configuration was locked. Among them, compounds C1 and C2 displayed the best activity, with tubulin polymerization IC

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Colchicine; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Molecular Docking Simulation; Molecular Structure; Polymerization; Structure-Activity Relationship

Cancer combination therapy based on drug co-delivery systems provides an effective strategy for enhancing treatment efficacy and reducing side effects. In this work, a new strategy through co-delivery of combretastatin A4 disodium phosphate (CA4P) and cisplatin (CDDP) was developed for the local treatment of colon cancer, through an in situ thermo-gelling hydrogel (mPEG-b-PELG). The results indicated that this material possessed concentration-dependent thermogelling properties and tunable in vivo biodegradability. Also, the drug loaded gel could regulate the in vitro drug release behaviors of both CDDP and CA4P, which promoted the in vivo vessel disrupting effects of CA4P compared with a free drug after local treatment for 48 h. Although the drug co-loaded gel induced less in vitro cell death compared with the free drug co-treated group, this drug co-loaded gel depot showed the highest antitumor efficacy compared with the other experimental groups after peritumoral injection toward C26 tumor bearing mice.

Topics: Animals; Cell Line, Tumor; Cell Survival; Cisplatin; Colonic Neoplasms; Drug Liberation; Female; Humans; Hydrogels; Mice, Inbred BALB C; Peptides; Polymers; Stilbenes; Transplantation, Heterologous; Tumor Microenvironment

A recent ultrasound imaging technique-shear wave elastography-showed its ability to image and quantify the mechanical properties of biological tissues, such as prostate or liver tissues. In the present study this technique was used to evaluate the relationship among tumor growth, stiffness and reduction of treatment with combretastatin (CA4 P) in allografted colon tumor CT26 in mice. During 12 d, CT26 tumor growth (n = 52) was imaged by ultrasound, and shear modulus was quantified, showing a good correlation between tumor volume and stiffness (r = 0.59). The treatment was initiated at d 12 and monitored every d during 4 d. Following the treatment, the tumor volume had decreased, while the elasticity of the tumor volume remained steady throughout the treatment. After segmentation using the shear modulus map, a detailed analysis showed a decrease in the stiffness after treatment. This reduction in the mechanical properties was shown to correlate with tissue reorganization, particularly, fibrosis and necrosis, assessed by histology.

Topics: Animals; Antineoplastic Agents, Phytogenic; Colon; Colonic Neoplasms; Disease Models, Animal; Elasticity Imaging Techniques; Female; Mice; Mice, Inbred BALB C; Stilbenes; Treatment Outcome

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; beta-Lactams; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Drug Resistance, Neoplasm; Glucuronates; HT29 Cells; Humans; Inactivation, Metabolic; Stilbenes; Structure-Activity Relationship

Docking studies of tubulin-targeting C2-substituted 7-deazahypoxanthine analogues of marine alkaloid rigidins led to the design and synthesis of compounds containing linear C2-substituents. The C2-alkynyl analogue was found to have double- to single-digit nanomolar antiproliferative IC50 values and showed statistically significant tumor size reduction in a colon cancer mouse model at nontoxic concentrations. These results provide impetus and further guidance for the development of these rigidin analogues as anticancer agents.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Colchicine; Colonic Neoplasms; Drug Design; Drug Screening Assays, Antitumor; Female; Humans; Marine Toxins; Mice; Mice, Nude; Models, Molecular; Molecular Docking Simulation; Structure-Activity Relationship; Tubulin; Tubulin Modulators; Xanthines

Nanocarrier-based anti-tumor drugs hold great promise for reducing side effects and improving tumor-site drug retention in the treatment of solid tumors. However, therapeutic outcomes are still limited, primarily due to a lack of drug penetration within most tumor tissues. Herein, we propose a strategy using a nanocarrier-based combination of vascular disrupting agents (VDAs) and cytotoxic drugs for solid tumor therapy. Specifically, combretastatin A-4 (CA4) serves as a "cannon" by eradicating tumor cells at a distance from blood vessels; concomitantly, doxorubicin (DOX) serves as a "pawn" by killing tumor cells in close proximity to blood vessels. This "cannon and pawn" combination strategy acts without a need to penetrate every tumor cell and is expected to eliminate all tumor cells in a solid tumor. In a murine C26 colon tumor model, this strategy proved effective in eradicating greater than 94% of tumor cells and efficiently inhibited tumor growth with a weekly injection. In large solid tumor models (C26 and 4T1 tumors with volumes of approximately 250 mm(3)), this strategy also proved effective for inhibiting tumor growth. These results showing remarkable inhibition of tumor growth provide a valuable therapeutic choice for solid tumor therapy.

Topics: Animals; Antineoplastic Agents, Phytogenic; Colonic Neoplasms; Disease Models, Animal; Doxorubicin; Drug Carriers; Drug Therapy, Combination; Mice; Nanoparticles; Stilbenes; Treatment Outcome

By switching position of the N and S atom in the thiazole ring which were similar to the previously reported agent 5-(4-ethoxyphenyl)-4-(3',4',5'-trimethoxyphenyl)thiazol-2-amine, a series of 4,5-diarylthiazole derivatives were synthesized using Friedel-Crafts reaction based on chemical modification of Combrestatatin A-4 (CA-4). Their antiproliferative activities were evaluated and identified as new microtubule destabilizing agents. Structure-activity relationship study indicated that compound 8a with 3,4,5-trimethoxyphenyl group at the C-4 position and 4-ethoxyphenyl group at the C-5 position of 2-amino substituted thiazole was of the most potent inhibitory activity in this series. 8a was found to exhibit the IC50 values of 8.4-26.4nM in five human cancer cell lines, with comparable inhibition effects to CA-4. Moreover, 8a showed potency as a tubulin polymerization inhibitor, with colchicine site binding ability and comparable extent of inhibition against the growth of P-glycoprotein over-expressing multidrug resistant cell lines. Mechanism studies revealed that 8a could block the progression of cell cycle in the G2/M phase and result in cellular apoptosis in cancer cells. As a new tubulin destabilizing agent, 8a was also found high antivascular activity as it concentration-dependently reduced the cell migration and disrupted capillary like tube formation of HUVEC cells. Furthermore, 8a significantly suppressed the tumor growth in HCT116 and SK-OV-3 xenograft models with tumor growth inhibitory rate of 55.12% and 72.7%, respectively. Our studies highlighted that 8a was a promising microtubule targeting antitumor agent.

Topics: Angiogenesis Inhibitors; Animals; Antimitotic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; Binding Sites; Cell Line, Tumor; Cell Movement; Colchicine; Colonic Neoplasms; Drug Resistance, Neoplasm; Female; G2 Phase Cell Cycle Checkpoints; Gene Expression; Human Umbilical Vein Endothelial Cells; Humans; Mice; Mice, Inbred BALB C; Protein Binding; Stilbenes; Structure-Activity Relationship; Thiazoles; Tubulin Modulators; Xenograft Model Antitumor Assays

Drug delivery of combined cytotoxic and antivascular chemotherapies in multidrug nanoassemblies may represent an attractive way to improve the treatment of experimental cancers. Here we made the proof of concept of this approach on the experimental LS174-T human colon carcinoma xenograft nude mice model. Briefly, we have nanoprecipitated the anticancer compound gemcitabine conjugated with squalene (SQ-gem) together with isocombretastatin A-4 (isoCA-4), a new isomer of the antivascular combretastatin A-4 (CA-4). It was found that these molecules spontaneously self-assembled as stable nanoparticles (SQ-gem/isoCA-4 NAs) of ca. 142 nm in a surfactant-free aqueous solution. Cell culture viability tests and apoptosis assays showed that SQ-gem/isoCA-4 NAs displayed comparable antiproliferative and cytotoxic effects than those of the native gemcitabine or the mixtures of free gemcitabine with isoCA-4. Surprisingly, it was observed by confocal microscopy that the nanocomposites made of SQ-gem/isoCA-4 distributed intracellularly as intact nanoparticles whereas the SQ-gem nanoparticles remained localized onto the cell membrane. When used to deliver these combined chemotherapeutics to human colon cancer model, SQ-gem/isoCA-4 nanocomposites induced complete tumor regression (by 93%) and were found superior to all the other treatments, whereas the overall tolerance was better than the free drug treatments. This approach could be applied to other pairs of squalenoylated nanoassemblies with other non-water-soluble drugs, thus broadening the application of the "squalenoylation" concept in oncology.

Topics: Animals; Antineoplastic Agents; Biological Transport; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Deoxycytidine; Drug Carriers; Drug Design; Gemcitabine; Humans; Intracellular Space; Mice; Nanocomposites; Squalene; Stilbenes; Xenograft Model Antitumor Assays

We examined the concept of a novel prodrug strategy in which anticancer drug can be locally released by visible/near IR light, taking advantage of the photodynamic process and photo-unclick chemistry. Our most recently formulated prodrug of combretastatin A-4, Pc-(L-CA4)2, showed multifunctionality for fluorescence imaging, light-activated drug release, and the combined effects of PDT and local chemotherapy. In this formulation, L is a singlet oxygen cleavable linker. Here, we advanced this multifunctional prodrug by adding a tumor-targeting group, folic acid (FA). We designed and prepared four FA-conjugated prodrugs 1-4 (CA4-L-Pc-PEGn-FA: n = 0, 2, 18, ∼45) and one non-FA-conjugated prodrug 5 (CA4-L-Pc-PEG18-boc). Prodrugs 3 and 4 had a longer PEG spacer and showed higher hydrophilicity, enhanced uptake to colon 26 cells via FR-mediated mechanisms, and more specific localization to SC colon 26 tumors in Balb/c mice than prodrugs 1 and 2. Prodrug 4 also showed higher and more specific uptake to tumors, resulting in selective tumor damage and more effective antitumor efficacy than non-FA-conjugated prodrug 5. FR-mediated targeting seemed to be an effective strategy to spare normal tissues surrounding tumors in the illuminated area during treatment with this prodrug.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Colonic Neoplasms; Drug Design; Female; Folate Receptors, GPI-Anchored; Folic Acid; Mice, Inbred BALB C; Molecular Structure; Optical Imaging; Photochemotherapy; Prodrugs; Stilbenes; Tissue Distribution; Xenograft Model Antitumor Assays

A series of novel 1,4-diaryl-2-azetidinones were synthesized and evaluated for antiproliferative activity, cell cycle effects, and apoptosis induction. Strong cytotoxicity was observed with the best compounds (±)-trans-20, (±)-trans-21, and enantiomers (+)-trans-20 and (+)-trans-21, which exhibited IC(50) values of 3-13 nM against duodenal adenocarcinoma cells. They induced inhibition of tubulin polymerization and subsequent G2/M arrest. This effect was accompanied by activation of AMP-activated protein kinase (AMPK), activation of caspase-3, and induction of apoptosis. Additionally, the most potent compounds displayed antiproliferative activity against different colon cancer cell lines, opening the route to a new class of potential therapeutic agents against colon cancer.

Topics: AMP-Activated Protein Kinases; Antineoplastic Agents; Apoptosis; Azetidines; Caspase 3; Cell Division; Cell Line, Tumor; Colonic Neoplasms; Drug Screening Assays, Antitumor; Duodenal Neoplasms; Enzyme Activators; G2 Phase; Humans; Stereoisomerism; Structure-Activity Relationship; Tubulin Modulators

To investigate the potential value of magnetic resonance (MR) elastography and diffusion-weighted (DW) MR imaging in the detection of microstructural changes of murine colon tumors during growth and antivascular treatment.. The study was approved by the regional ethics committee for animal care. Sixty Balb-C mice, bearing ectopic and orthotopic colon tumors, were monitored for 3 weeks with high-resolution T2-weighted MR imaging, three-dimensional steady-state MR elastography, and DW MR imaging at 7 T. The same imaging protocol was performed 24 hours after injection of combretastatin A4 phosphate (CA4P) in 12 mice. The absolute value of the complex shear modulus (|G*|) and the apparent diffusion coefficient (ADC) were measured in the viable zones of tumors and compared with microvessel density (MVD), cellularity, and micronecrosis by using the Pearson correlation coefficient.. During tumor growth, |G*| increase was correlated with MVD (r = 0.70 [P = .08] and r = 0.78 [P = .002], for both the ectopic and orthotopic models, respectively). Moreover, the ectopic tumors displayed decreased ADC, which correlated with increased cellularity (r = 0.77, P = .04), whereas no changes in ADC and cellularity were observed in orthotopic tumors. After CA4P administration, |G*| decreased in the ectopic model (P < .0001), similar to the MVD evolution (P = .03), whereas no significant changes in |G*| (P = .7) and MVD (P = .6) were observed in the orthotopic model. ADC increased in both models (P = .047 and P = .01 for the ectopic and the orthotopic models, respectively) in relation to increased micronecrosis.. Imaging of mechanical properties and diffusivity provide complementary information during tumor growth and regression that are respectively linked to vascularity and tumor cell alterations, including cellularity and micronecrosis.

Topics: Animals; Colonic Neoplasms; Diffusion Magnetic Resonance Imaging; Elasticity Imaging Techniques; Female; Mice; Mice, Inbred BALB C; Microcirculation; Neovascularization, Pathologic; Stilbenes

Recent clinical data demonstrated that the vascular targeting agent Combretastatin-A4 phosphate (CA-4P) prolonged survival of patients with advanced anaplastic thyroid cancer without any adverse side effects. However, as a single agent CA-4 failed to reduce tumour growth in the murine CT-26 adenocarcinoma colon cancer model. Furthermore, the molecular mechanism of the innate resistance of HT-29 human adenocarcinoma cells to CA-4 is largely unknown. In this report, we demonstrate for the first time that prolonged exposure to CA-4 and an azetidinone cis-restricted analogue, CA-432 (chemical name; 4-(3-Hydroxy-4-methoxyphenyl)-3-phenyl-1-(3,4,5-trimethoxyphenyl)-azetidin-2-one) induced autophagy in adenocarcinoma-derived CT-26, Caco-2 and HT-29 cells but not in fibrosarcoma-derived HT-1080 cells. Autophagy is a fundamental self-catabolic process which can facilitate a prolonged cell survival in spite of adverse stress by generating energy via lysosomal degradation of cytoplasmic constituents. Autophagy was confirmed by acridine orange staining of vesicle formation, electron microscopy and increased expression of LC3-II. Combretastatin-induced autophagy was associated with a loss of mitochondrial membrane potential and elongation of the mitochondria. Furthermore, inhibition of autophagy by the vacuolar H(+)ATPase inhibitor Bafilomycin-A1 (BAF-A1) significantly enhanced CA-432 induced HT-29 cell death. Both CA-4 and its synthetic derivative, CA-432 induced the formation of large hyperdiploid cells in Caco-2 and CT-26 cells. The formation of these polyploid cells was significantly inhibited by autophagy inhibitor, BAF-A1. Results presented within demonstrate that autophagy is a novel response to combretastatin exposure and may be manipulated to enhance the therapeutic efficacy of this class of vascular targeting agents.

Topics: Adenocarcinoma; Autophagy; Blotting, Western; Caspase 3; Caspase 7; Cell Line, Tumor; Colonic Neoplasms; Flow Cytometry; Humans; Membrane Potentials; Microscopy, Electron; Mitochondria; Stilbenes

The present study indicated that the combination of TRAIL/Apo-2L and CA-4 exerted synergistic anti-proliferative effect against human colon carcinoma cells including SW-620 and HCT-116 in vitro. Moreover, the increased anti-tumor efficacy of TRAIL/Apo-2L combined with CA-4 was further validated on SW-620 xenograft model in nude mice. These enhanced anti-cancer activities were accompanied by caspase-mediated apoptosis. Furthermore, it was identified that NF-κB as the major determinant of TRAIL/Apo-2L resistance could be blocked in cytoplasm by TRAIL/Apo-2L plus CA-4 treatment. Taken together, these findings build the rationale for further (pre)clinical development of TRAIL/Apo-2L and CA-4 against colorectal cancer.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Caspases; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Synergism; HCT116 Cells; Humans; Immunoblotting; Mice; Mice, Nude; NF-kappa B; Poly(ADP-ribose) Polymerases; Protein Transport; Stilbenes; TNF-Related Apoptosis-Inducing Ligand; Xenograft Model Antitumor Assays

Although there is a need to enhance the therapeutic efficiency in cancer by combining immunotherapeutic procedures with other therapy, combination with chemotherapy is complicated due to immunosuppressive effects of most chemotherapeutic drugs. The purpose of this investigation was to study whether combining tumor cell immunization with the vascular targeting drug combretastatin A4 phosphate (CA4P) would enhance tumor retardation and/or affect the antitumor immune response.. Rats with intrahepatic colon carcinoma were immunized weekly with IL-18/IFNgamma-transfected tumor cells, starting day 9, and were treated with a low-dose CA4P (2 mg/kg, 5 days a week starting day 7). The effect of CA4P was studied on tumor growth and on immune reactivity in vitro.. Rats with preexisting tumor, immunized and treated with low-dose CA4P, had a significantly retarded tumor growth compared with rats receiving CA4P or immunization alone. Splenocytes from rats treated with this combination had a significantly enhanced antitumor immune response compared with splenocytes from control rats. Exposure of nonadherent splenocytes to CA4P in vitro did not enhance their proliferation. However, 3-hour pretreatment of adherent splenocytes with 0.3 microg/mL CA4P significantly enhanced proliferation and IFNgamma production of admixed nonadherent splenocytes, partly due to nitric oxide reduction. Combining the nitric oxide synthase inhibitor N-nitro-l-arginine methyl ester with CA4P and immunization further retarded tumor growth.. Concomitant treatment of rats with progressively growing tumor with immunization and low-dose CA4P significantly enhances the therapeutic effect as compared with either treatment alone and results in an enhanced antitumor immune reactivity.

Topics: Administration, Oral; Animals; Carcinoma; Cell Proliferation; Colonic Neoplasms; Dose-Response Relationship, Drug; Dose-Response Relationship, Immunologic; Humans; Injections, Intraperitoneal; Interferon-gamma; NG-Nitroarginine Methyl Ester; Nitric Oxide; Rats; Rats, Inbred BN; Rats, Inbred WF; Stilbenes; Structure-Activity Relationship; Transplantation, Heterologous; Xenograft Model Antitumor Assays

A functional vascular network is essential for the survival, growth and spread of solid tumours, making blood vessels a key target for therapeutic strategies. Combretastatin A-4 phosphate (CA-4-P) is a tubulin-depolymerising agent in Phase II clinical trials as a vascular disrupting agent. Not much is known of the molecular effect of CA-4-P under tumour conditions. The tumour microenvironment differs markedly from that in normal tissue, specifically with respect to oxygenation (hypoxia). Gene regulation under tumour conditions is governed by hypoxia inducible factor 1 (HIF-1), controlling angiogenic and metastatic pathways.. We investigated the effect of CA-4-P on factors of the upstream and downstream signalling pathway of HIF-1 in vitro.. CA-4-P treatment under hypoxia tended to reduce HIF-1 accumulation in a concentration-dependent manner, an effect which was more prominent in endothelial cells than in cancer cell lines. Conversely, CA-4-P increased HIF-1 accumulation under aerobic conditions in vitro. At these concentrations of CA-4-P under aerobic conditions, nuclear factor kappaB was activated via the small GTPase RhoA, and expression of the HIF-1 downstream angiogenic effector gene, vascular endothelial growth factor (VEGF-A), was increased.. Our findings advance the understanding of signal transduction pathways involved in the actions of the anti-vascular agent CA-4-P.

Topics: Antineoplastic Agents, Phytogenic; Carcinoma; Colonic Neoplasms; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1; Signal Transduction; Stilbenes; Tumor Cells, Cultured; Urinary Bladder Neoplasms

The effects of two anti-vascular agents, combretastatin A4 phosphate (CA4P), and 5,6-dimethylxanthenone-4-acetic acid (DMXAA), on the perfusion of two human colon adenocarcinomas implanted in SCID mice, were assessed for up to 3 h using non-invasive magnetic resonance imaging (MRI) and spectroscopy techniques (MRS). MRI measurements of GdDTPA inflow showed that treatment with CA4P had little effect on the perfusion of HT29 tumours. Localized (31)P MRS measurements also showed that the drug had no significant effect on tumour cell energy status, as assessed from the ratio of the integrals of the signals from inorganic phosphate (P(i)) and nucleoside triphosphates. However, after treatment with DMXAA, perfusion was reduced and the P(i)/NTP ratio increased, indicating that the HT29 tumour is susceptible to the action of this drug. The LS174T tumour model was susceptible to both CA4P and DMXAA, using the criteria of changes in GdDTPA inflow and P(i)/NTP ratio.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Colonic Neoplasms; Contrast Media; Gadolinium DTPA; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Mice; Mice, SCID; Stilbenes; Transplantation, Heterologous; Xanthenes; Xanthones

Solid tumors have a heterogeneous pathophysiology, which has a major impact on therapy. Using SW1222 colorectal xenografts grown in nude mice, we have shown that antibody-targeted radioimmunotherapy (RIT) effectively treated the well-perfused tumor rim, producing regressions for approximately 35 days, but was less effective at the more hypoxic center. By 72 h after RIT, the number of apoptotic cells rose from an overall value of 1% in untreated tumors to 35% at the tumor periphery and 10% at the center. The antivascular agent disodium combretastatin A-4 3-O-phosphate (CA4-P) rapidly reduced tumor blood flow to 62% of control values by 1 h, 23% by 3 h, and between 32-36% from 6 to 24 h after administration. This created central hemorrhagic necrosis, but a peripheral rim of cells continued to grow, and survival was unaffected. Changes in the pattern of perfusion across the tumor over time were zonal. Untreated mice showed perfusion throughout the tumor, with greatest activity at the rim. There was an overall reduction at 1 h, and total cessation of central perfusion from 3 h onward. A narrow peripheral rim of perfusion was always present, which increased in intensity and extent between 6 and 24 h, either through reperfusion or new vessel growth. Combining these two complementary therapies (7.4 MBq (131)I-labeled anti-carcinoembryonic antigen IgG i.v. plus a single 200 mg/kg dose of CA4-P i.p.) produced complete cures in five of six mice for >9 months. Allowing maximal tumor localization of antibody (48 h) before blood flow inhibition by CA4-P increased tumor retention by two to three times control levels by 96 h without altering normal tissue levels, as confirmed by gamma counting and phosphor image analysis. The success of this combined, synergistic therapy was probably the result of several factors: (a) the killing of tumor cells in the outer, radiosensitive region by targeted radiotherapy; (b) enhancement of RIT by entrapment of additional radioantibody after combretastatin-induced vessel collapse; and (c) destruction of the central, more hypoxic and radioresistant region by CA4-P. This work demonstrates the need to consider cancer treatment in a biologically heterogeneous setting, if results are to be effectively translated to the clinic.

Topics: Adenocarcinoma; Animals; Antibodies, Monoclonal; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Division; Colonic Neoplasms; Combined Modality Therapy; Female; Humans; Immunotoxins; Iodine Radioisotopes; Mice; Mice, Nude; Radioimmunotherapy; Stilbenes; Tissue Distribution; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

A series of combretastatin A-4 (CA-4) analogues were synthesized, and their cytotoxic effects against murine Colon 26 adenocarcinoma and inhibitory activity on tubulin polymerization were evaluated. Since CA-4 has limited aqueous solubility, the target compounds were designed to improve solubility by introduction of a nitrogen-containing group. Among the compounds synthesized, those with an amino moiety in place of the phenolic OH of CA-4 showed potent antitubulin activity and cytotoxicity against murine Colon 26 adenocarcinoma in vitro. Some of the compounds which were potent in vitro were evaluated in the murine tumor model Colon 26 in vivo. Among these, 13bHCl, 21aHCl, and 21bHCl showed significant antitumor activity in the animal model, while CA-4 was ineffective. 13bHCl and 21aHCl were further evaluated in two murine tumor models (Colon 38 and 3LL) and human xenografts HCT-15. These compounds showed potent antitumor activity comparable or superior to that of CDDP. The structure-activity relationships of this series of compounds are also discussed.

Topics: Acrylonitrile; Adenocarcinoma; Aniline Compounds; Animals; Anisoles; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Biopolymers; Cell Survival; Colonic Neoplasms; Drug Screening Assays, Antitumor; Humans; Mice; Neoplasm Transplantation; Solubility; Stilbenes; Structure-Activity Relationship; Transplantation, Heterologous; Tubulin; Tumor Cells, Cultured

As part of our continuing search for potential anticancer drug candidates in the 2-phenyl-4-quinolone series, we have synthesized a series of 6,7-methylenedioxy-substituted and unsubstituted 2-phenyl-4-quinolones, as well as related compounds. Their in vitro inhibition of human tumor cell lines and tubulin polymerization is reported. In general, a good correlation was found between cytotoxicity and inhibition of tubulin polymerization. Compounds 7, 9, 13, 16, 22, 23, 36, and 37 showed potent inhibitory effects in both assays. All rigid analogs (47-49) and trimethoxy-substituted compounds showed little or no activity. Substitution at the 4'-position also resulted in compounds with little or no activity, except for hydroxyl or methyl groups at this position. Further investigation is underway to determine if substitution at the 3'-position will result in compounds with increased activity.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Carcinoma, Small Cell; Cattle; Cell Division; Central Nervous System Neoplasms; Colonic Neoplasms; Female; Humans; Leukemia; Lung Neoplasms; Molecular Structure; Polymers; Quinolones; Structure-Activity Relationship; Tubulin; Tubulin Modulators; Tumor Cells, Cultured

A series of stilbenes has been prepared and tested for cytotoxicity in the five human cancer cell lines A-549 non-small cell lung, MCF-7 breast, HT-29 colon, SKMEL-5 melanoma, and MLM melanoma. The cis stilbenes 6a-f proved to be cytotoxic in all five cell lines, with potencies comparable to that of combretastatin A-4. These cytotoxic compounds were all potent inhibitors of tubulin polymerization. The corresponding trans stilbenes 7b-f were inactive as tubulin polymerization inhibitors and were significantly less cytotoxic in the five cancer cell lines. In the dihydro series, 8b, 8c, and 8f were inactive as tubulin polymerization inhibitors, while 8a, 8d, and 8e were less active than the corresponding cis compounds 6a, 6d, and 6e. The lack of tubulin polymerization inhibitory activity and cytotoxicity displayed by the phenanthrene 23b, which was synthesized as a conformationally rigid analogue of the lead compound 1, indicates that the activity of the stilbenes is not due to a totally planar conformation. Similarly, inactivity of the conformationally restricted analogue 26 suggests that the biologically active conformation of 1a resembles that of the cis alkene 1. Additional inactive compounds prepared include the benzylisoquinoline series 28-32 as well as the protoberberines 38 and 39. Shortening the two-carbon bridge of 1a to a one-carbon bridge in the diphenylmethane 20 resulted in a decrease in cytotoxicity and tubulin polymerization inhibitory activity. Although the corresponding benzophenone 18 was as active as 1a as a tubulin polymerization inhibitor, it was less cytotoxic than 1a, and the benzhydrol 19 was essentially inactive. With the exception of the amide 15c, which displayed low antitubulin activity, all of the phenylcinnamic acid derivatives 14a-c and 15a-f were inactive in the tubulin polymerization inhibition assay. The acid 14b and the ester 15a were cytotoxic in several of the cancer cell cultures in spite of their inactivity as tubulin polymerization inhibitors.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Division; Colonic Neoplasms; Humans; Lung Neoplasms; Melanoma; Stilbenes; Structure-Activity Relationship; Tubulin; Tubulin Modulators; Tumor Cells, Cultured

An array of cis-, trans-, and dihydrostilbenes and some N-arylbenzylamines were synthesized and evaluated for their cytotoxicity in the five cancer cell cultures A-549 lung carcinoma, MCF-7 breast carcinoma, HT-29 colon adenocarcinoma, SKMEL-5 melanoma, and MLM melanoma. Several cis-stilbenes, structurally similar to combretastatins, were highly cytotoxic in all five cell lines and these were also found to be active as inhibitors of tubulin polymerization. The most active compounds also inhibited the binding of colchicine to tubulin. The most potent of the new compounds, both as a tubulin polymerization inhibitor and as a cytotoxic agent, was (Z)-1-(4-methoxyphenyl)-2-(3,4,5-trimethoxyphenyl)ethene (5a). This substance was almost as potent as combretastatin A-4 (1a), the most active of the combretastatins, as a tubulin polymerization inhibitor. Compound 5a was found to be approximately 140 times more cytotoxic against HT-29 colon adenocarcinoma cells and about 10 times more cytotoxic against MCF-7 breast carcinoma cells than combretastatin A-4. However, 5a was found to be about 20 times less cytotoxic against A-549 lung carcinoma cells, 30 times less cytotoxic against SKMEL-5 melanoma cells, and 7 times less cytotoxic against MLM melanoma cells than combretastatin A-4. The relative potencies 5a greater than 8a greater than 6a for the cis, dihydro, and trans compounds, respectively, as inhibitors of tubulin polymerization are in agreement with the relative potencies previously observed for combretastatin A-4 (1a), dihydrocombretastatin A-4 (1c), and trans-combretastatin A-4 (1b). The relative potencies 5a greater than 8a greater than 6a were also reflected in the results of the cytotoxicity assays. Structure-activity relationships of this group of compounds are also discussed.

Topics: Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Breast Neoplasms; Chemical Phenomena; Chemistry; Colchicine; Colonic Neoplasms; Humans; Lung Neoplasms; Melanoma; Molecular Structure; Polymers; Stilbenes; Structure-Activity Relationship; Tubulin; Tubulin Modulators; Tumor Cells, Cultured

The African tree Combretum caffrum (Combretacae) has been found to contain a powerful inhibitor of tubulin polymerization (IC50 2-3 microM), the growth of murine lymphocytic leukemia (L 1210 and P 388 with ED50 approximately 0.003 microM and human colon cancer cell lines [(e.g. LoVo (ED50 = 0.005 microgram/ml), HT 29 (ED50 0.02 microgram/ml, Colo 205 (ED50 = 0.07 microgram/ml), DLD-1 (ED50 = 0.005 microgram/ml) and HCT-15 (ED50 = 0.0009 microgram/ml] designated combretastatin A-4 (1c). The structure assigned by spectral techniques was confirmed by synthesis.

Topics: Animals; Antineoplastic Agents, Phytogenic; Bibenzyls; Colonic Neoplasms; Humans; Leukemia L1210; Leukemia P388; Magnetic Resonance Spectroscopy; Mass Spectrometry; Mice; Molecular Structure; Plant Extracts; Stilbenes; Tubulin Modulators; Tumor Cells, Cultured