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Tumor angiogenesis is a degenerate process regulated by a complex network of proangiogenic factors. Existing antiangiogenic drugs used in clinic are characterized by selectivity for specific factors. Antiangiogenic properties might be improved in drugs that target multiple factors and thereby address the inherent mechanistic degeneracy in angiogenesis. Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) family members and their cognate receptors are key players in promoting tumor angiogenesis. Here we report the pharmacologic profile of E-3810, a novel dual inhibitor of the VEGF and FGF receptors. E-3810 potently and selectively inhibited VEGF receptor (VEGFR)-1, -2, and -3 and FGF receptor (FGFR)-1 and -2 kinases in the nanomolar range. Ligand-dependent phosphorylation of VEGFR-2 and FGFR-1 was suppressed along with human vascular endothelial cell growth at nanomolar concentrations. In contrast, E-3810 lacked cytotoxic effects on cancer cell lines under millimolar concentrations. In a variety of tumor xenograft models, including early- or late-stage subcutaneous and orthotopic models, E-3810 exhibited striking antitumor properties at well-tolerated oral doses administered daily. We found that E-3810 remained active in tumors rendered nonresponsive to the general kinase inhibitor sunitinib resulting from a previous cycle of sunitinib treatment. In Matrigel plug assays performed in nude mice, E-3810 inhibited basic FGF–induced angiogenesis and reduced blood vessel density as assessed by histologic analysis. Dynamic contrast-enhanced magnetic resonance imaging analysis confirmed that E-3810 reduced the distribution of angiogenesis-sensitive contrast agents after only 5 days of treatment. Taken together, our findings identify E-3810 as a potent antiangiogenic small molecule with a favorable pharmacokinetic profile and broad spectrum antitumor activity, providing a strong rationale for its clinical evaluation. Cancer Res; 71(4); 1396–405. ©2011 AACR.

Mismatch DNA repair deficiency is associated with resistance to certain major groove alkylating agents including methylating agents and cisplatin. We have now studied the relevance of mismatch repair alterations to the cytotoxicity induced by drugs which alkylate N3 adenines in the minor groove of DNA. We have used the mismatch repair defective human colocarcinoma cell line HCT-116 which has a mutation in the hMLH1 gene, and a subline where hMLH1 expression is restored by chromosome 3 transfer (HCT-116+ch3). We have tested three alkylating minor groove binders (tallimustine, carzelesin and CC1065) and one non-covalent minor groove binder (PNU 151807). The HCT-116+ch3 subline was more sensitive than the parental line to the treatment with the three alkylating minor groove binders, while the non-alkylating compound had a similar activity in both cell lines. Further support for mismatch repair being involved in sensitivity of the minor groove alkylators is that two cisplatin-resistant sublines of the human ovarian adenocarcinoma cell line A2780 (A2780/CP70 and A2780/MCP-1) are defective in hMLH1 expression and are more resistant to these agents than the parental mismatch repair proficient cells. Furthermore, the restoration of hMLH1 activity in the A2780/CP70 cell line, by introduction of chromosome 3, was associated with an increased sensitivity to the three alkylating minor groove binders. Again, the non-covalent minor groove binder was equally effective in mismatch repair deficient and proficient clones. The data indicate that mismatch repair deficiency mediated by loss of hMLH1 expression is associated not only with drug-resistance to major groove binders, but also to minor groove binders. However, loss of mismatch repair does not mediate resistance to the non-covalent minor groove binder PNU 151807. © 1999 Cancer Research Campaign

By using electromobility shift assay (EMSA), we have identified a protein able to recognize the DNA only if it was previously reacted with minor groove binders. This protein binds with very high affinity AT containing DNA treated with minor groove binders such as distamycin A, Hoechst 33258 and 33342, CC-1065 and ethidium bromide minor groove intercalator, but not with major groove binders such as quinacrine mustard, cisplatin or melphalan, or with topoisomerase I inhibitor camptothecin or topoisomerase II inhibitor doxorubicin. This protein was found to be present in different extracts of human, murine and hamster cells, with the human protein which appears to have a molecular weight slightly lower than that of the other species. This protein was found to be expressed both in cancer and normal tissues. By using molecular ultrafiltration techniques as well as southwestern analysis it was estimated that the apparent molecular weight is close to 100 kDa. We can exclude an identity between this protein and other proteins, with a similar molecular weight previously reported to be involved in DNA damage recognition/repair, such as topoisomerase I, mismatch repair activities such as the prokaryotic MutS protein and its human homologue hMSH2 or proteins of the nucleotide excision repair system such as ERCC1, -2, -3 and -4.

E-3810 is a novel small molecule that inhibits VEGF receptor-1, -2, and -3 and fibroblast growth factor receptor-1 tyrosine kinases at nmol/L concentrations currently in phase clinical II. In preclinical studies, it had a broad spectrum of antitumor activity when used as monotherapy in a variety of human xenografts. We here investigated the activity of E-3810 combined with different cytotoxic agents in a MDA-MB-231 triple-negative breast cancer xenograft model. The molecule could be safely administered with 5-fluorouracil, cisplatin, and paclitaxel. The E-3810–paclitaxel combination showed a striking activity with complete, lasting tumor regressions; the antitumor activity of the combination was also confirmed in another triple-negative breast xenograft, MX-1. The activity was superior to that of the combinations paclitaxel+brivanib and paclitaxel+sunitinib. Pharmacokinetics studies suggest that the extra antitumor activity of the combination is not due to higher paclitaxel tumor levels, which in fact were lower in mice pretreated with all three kinase inhibitors, and the paclitaxel plasma levels excluded reduced drug availability. Pharmacodynamic studies showed that E-3810, brivanib, and sunitinib given as single agents or in combination with paclitaxel reduced the number of vessels, but did not modify vessel maturation. Reduced tumor collagen IV and increased plasma collagen IV, associated with increased matrix metalloproteinases (MMP), particularly host MMP-9, indicate a proteolytic remodeling of the extracellular matrix caused by E-3810 that in conjunction with the cytotoxic effect of paclitaxel on the tumor cells (caspase-3/7 activity) may contribute to the striking activity of their combination. These data support the therapeutic potential of combining E-3810 with conventional chemotherapy. Mol Cancer Ther; 12(2); 131–40. ©2012 AACR.

A collateral sensitivity or a very modest cross-resistance to BBR 3464 was found in 2 ovarian cancer cell lines with experimentally induced resistance to cisplatin. Loss of mismatch repair proteins (hMLH1, hPMS2) or overexpression of nucleotide excision repair proteins (ERCC1) was not detrimental for the cellular sensitivity to BBR 3464. Moreover, interesting differences in the kinetics of formation and removal of DNA lesions at the single-gene (N- ras) level were observed between BBR 3464 and CDDP. © 2001 Cancer Research Campaign www.bjcancer.com

E-3810 is a small molecule inhibitor of VEGFR-1, -2 and -3 and FGFR-1 tyrosine kinases with IC50 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C192.

E-3810 is a novel small molecule that selectively inhibits VEGFR-1, -2 and -3 and FGFR-1 tyrosine kinases with IC50 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2574. doi:10.1158/1538-7445.AM2011-2574

Some DNA minor groove binders have shown antiviral and antitumor activity. The distamycin derivative Tallimustine and the CC-1065 derivative Adozelesin and Carzelesin are under clinical investigationin phase II clinical trials. The mechanisms of repair of the DNA lesions caused by these drugs are unknown. By using the gel retardation assay, we have identified a protein able to recognize a fragment of DNA only if it was previously reacted with minor groove binders (MGB). This protein binds with very high affinity AT containing DNA treated with MGB such as Distamycin A or Hoechst 33258 but not with a major groove binders (such as e.g. quinacrine mustard). This protein was found to be present in extracts of human, murine or hamster cells, although the human protein appears to have a molecular weight slightly lower than that of the other species. This protein is expressed both in cancer and normal tissues. By using ultrafiltration techniques as well as Southwestern analysis it was estimated that the apparent molecular weight is close to 100 Kda. Work is in progress to purify this protein which might be involved in the recognition and repair of DNA damage caused by minor groove binders.