3-4--5-trimethoxystilbene and Colonic-Neoplasms

(Z)-3,5,4'-Trimethoxystilbene (Z-TMS) is a resveratrol analog with increased antiproliferative activity towards a number of cancer cell lines compared to resveratrol, which has been shown to inhibit tubulin polymerization in vitro. The purpose of this study was to investigate if Z-TMS still shows potential for the prevention of metabolic diseases as known for resveratrol. Cell growth inhibition was determined with IC50 values for Z-TMS between 0.115μM and 0.473μM (resveratrol: 110.7μM to 190.2μM). Flow cytometric analysis revealed a G2/M arrest after Z-TMS treatment, whereas resveratrol caused S phase arrest. Furthermore, Z-TMS was shown to impair microtubule polymerization. Beneficial effects on lipid accumulation were observed for resveratrol, but not for Z-TMS in an in vitro steatosis model. (E)-Resveratrol was confirmed to elevate cAMP levels, and knockdown of AMPK attenuated the antiproliferative activity, while Z-TMS did not show significant effects in these experiments. SIRT1 and AMPK activities were further measured indirectly via induction of the target gene small heterodimer partner (SHP). Thereby, (E)-resveratrol, but not Z-TMS, showed potent induction of SHP mRNA levels in an AMPK- and SIRT1-dependent manner, as confirmed by knockdown experiments. We provide evidence that Z-TMS does not show beneficial metabolic effects, probably due to loss of activity towards resveratrol target genes. Moreover, our data support previous findings that Z-TMS acts as an inhibitor of tubulin polymerization. These findings confirm that the methylation of resveratrol leads to profound changes in the mode of action, which should be taken into consideration when conducting lead structure optimization approaches.

Topics: AMP-Activated Protein Kinases; Antineoplastic Agents; Caco-2 Cells; Cell Cycle Checkpoints; Cell Proliferation; Colonic Neoplasms; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Hep G2 Cells; HT29 Cells; Humans; Liver Neoplasms; Microtubules; Molecular Structure; Resveratrol; RNA Interference; Sirtuin 1; Stilbenes; Structure-Activity Relationship; Transfection; Tubulin Modulators

Based on the potential of resveratrol as a colon cancer chemopreventive agent, a set of 26 stilbenes were synthesized and tested against the colon cancer cell lines HT-29 and Caco-2. (Z)-4-(3,5-Dimethoxystyryl)aniline (4), (Z)-methyl-4-(3,5-dimethoxystyryl)benzoate (6), and (Z)-1,3-dimethoxy-5-(4-methoxystyryl)benzene (10) showed strong inhibitory activity in vitro. In vivo studies using HT-29 xenografts in immunodeficient mice were conducted with 4, 6 and 10, together with their corresponding trans isomers (3, 5, and 9, respectively), at the dose of 10 mg/kg body weight. Tumor volume was significantly lowered in 3-, 4-, and 9-treated groups. The cis- and trans-amino analogs (4 and 3, respectively) had similar effect on tumor growth, a 40% decrease compared to the control. Analysis of the serum revealed that 4 isomerized to 3, which may explain their similar effects in SCID mice. Stilbenes 5, 6, 9, and 10 retained their configurations in the serum. Stilbenes 6 and 10 lacked tumor-suppressive effect in SCID mice; the serum levels of these analogs were low (18.8 and 15.5 ng/mL, respectively). Stilbene 9, while weakly active in vitro demonstrated good activity in vivo, was found at higher levels in the serum (69.9 ng/mL) compared to 10. The anti-tumorigenic activity of these stilbene analogs may be partly linked to their effects on proteins involved in cell proliferation, as observed by lowered expression of proliferating cell nuclear antigen and upregulation of the cyclin-dependent kinase inhibitor, p27, in the tumor tissues. Overall, identification of the anti-tumorigenic potential of these compounds provides opportunities for their use against colorectal cancer.

Topics: Animals; Antineoplastic Agents; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Female; Humans; Mice; Proliferating Cell Nuclear Antigen; Stilbenes; Tumor Burden; Xenograft Model Antitumor Assays

Resveratrol (R-3), a trihydroxy trans-stilbene from grape, inhibits multistage carcinogenesis in animal models. Here we report that 3,5,4'-trimethoxystilbene (MR-3), the permethylated derivative of R-3 was more potent against the growth of human cancer cells (HT-29, PC-3, COLO 205) with estimated IC(50) values of 81.31,42.71, and 6.25 microM, respectively. We further observed that MR-3 induced apoptosis in COLO 205 cells through modulation of mitochondrial functions regulated by reactive oxygen species (ROS). ROS generation occurs in the early stages of MR-3-induced apoptosis, preceding cytochrome-c release, caspase activation, and DNA fragmentation. Significant therapeutic effects were demonstrated in vivo by treating severe combined immune deficiency (SCID) mice bearing COLO 205 tumor xenografts with MR-3 (50 mg/kg ip). Assays on DNA fragmentation and caspase activation were performed and demonstrated that apoptosis occurred in tumor tissues treated with MR-3. The appearance of apoptotic cells, as shown by Hematoxylin and Eosin (H&E) staining, and an increase in p21 and decrease in proliferating cell nuclear antigen (PCNA) protein by immuno-histochemistry were observed in tumor tissues under MR-3 treatment. Our study identifies the novel mechanisms of the antitumor effects of MR-3 and indicates that these results may have significant applications for cancer chemotherapy.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Caspases; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; DNA Fragmentation; Drug Evaluation, Preclinical; Enzyme Activation; Humans; Immunohistochemistry; Inhibitory Concentration 50; Membrane Potentials; Mice; Mice, SCID; Mitochondria; Molecular Structure; Proliferating Cell Nuclear Antigen; Reactive Oxygen Species; Stilbenes; Xenograft Model Antitumor Assays

(Z)-3,5,4'-Trimethoxystilbene is a natural polyphenol present in five different plants, Virola cuspidata, Virola elongata, Centipeda minima, Schoenus nigricans and Rheum undulatum. This molecule was prepared in a three-step sequence in good overall yield. The isomerisation from the (E)- to (Z)-isomer is performed using UV irradiation. Biological investigations were conducted on a human colon cancer cell line (Caco-2) with anti-mitotic activities. Growth was completely arrested at an added 0.4 microM level of (Z)-3,5,4'-trimethoxystilbene. This agent is 100-fold more active than resveratrol or (E)-3,5,4'-trihydroxystilbene, and the mechanism of this process involves an inhibition of tubulin polymerisation in a dose dependent manner.

Topics: Antineoplastic Agents, Phytogenic; Caco-2 Cells; Cell Cycle; Cell Proliferation; Colonic Neoplasms; Dose-Response Relationship, Drug; Electrophoresis, Agar Gel; Flow Cytometry; Humans; Mitosis; Resveratrol; Stereoisomerism; Stilbenes; Tubulin; Tubulin Modulators

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