Search

Introduction: CC-5079, a small molecule inhibitor of tubulin polymerization and phosphodiesterase-4 activity, was evaluated for antiangiogenic and antitumor activities. Materials and Methods: First, CC-5079 in vitro activity on human umbilical vein endothelial cells (HUVECs), fibroblasts, and MC38 were evaluated by proliferation, migration, and invasion assays. Second, CC-5079 effect on microvessel formation was evaluated ex vivo by chick chorioallantoic membrane (CAM), rat aortic rings assays, and with directed in vivo angiogenesis assay (DIVAA). Third, CC-5079 antitumor effect was determined in treatment of C57BL/6 mice with MC38 tumors. Finally, CC-5079 modulation of MKP1 in HUVECs, human fibroblast, and MC38 were determined by RNA isolation for qRT-PCR. Results: At the 0.1 μM concentration CC-5079 significantly inhibited HUVEC, fibroblast, and MC38 proliferation and migration (all P < 0.001). At the 0.1 μM concentration, CC-5079 also inhibited HUVEC invasion (P < 0.05) but not fibroblast. In the CAM and rat aortic ring assays, CC-5079 at 0.1 μM inhibited microvessel formation (P < 0.05). By DIVAA, CC-5079 at 1 mg/kg/d continuous delivered inhibited microvessel formation (P < 0.05). Intraperitoneal CC-5079 was well tolerated and inhibited the growth of subcutaneous MC38 at 100 mg/kg/d (P < 0.01). By qRT-PCR, CC-5079 stimulated MKP1 expression in HUVEC and fibroblast. Conclusion: CC-5079 demonstrated stimulation of MKP1, antiangiogenic, and antitumor properties. [ABSTRACT FROM AUTHOR]

Lenalidomide (Revlimid®; CC-5013) and pomalidomide (CC-4047) are IMiDs® proprietary drugs having immunomodulatory properties that have both shown activity in cancer clinical trials; lenalidomide is approved in the United States for a subset of MDS patients and for treatment of patients with multiple myeloma when used in combination with dexamethasone. These drugs exhibit a range of interesting clinical properties, including anti-angiogenic, anti-proliferative, and pro-erythropoietic activities although exact cellular target(s) remain unclear. Also, anti-inflammatory effects on LPS-stimulated monocytes (TNF-α is decreased) and costimulatory effects on anti-CD3 stimulated T cells, (enhanced T cell proliferation and proinflammatory cytokine production) are observed These drugs also cause augmentation of NK-cell cytotoxic activity against tumour-cell targets. Having shown that pomalidomide confers T cell-dependant adjuvant-like protection in a preclinical whole tumour-cell vaccine-model, we now show that lenalidomide and pomalidomide strongly inhibit T-regulatory cell proliferation and suppressor-function. Both drugs inhibit IL-2-mediated generation of FOXP3 positive CTLA-4 positive CD25high CD4+ T regulatory cells from PBMCs by upto 50%. Furthermore, suppressor function of pre-treated T regulatory cells against autologous responder-cells is abolished or markedly inhibited without drug related cytotoxicity. Also, Balb/C mice exhibit 25% reduction of lymph-node T regulatory cells after pomalidomide treatment. Inhibition of T regulatory cell function was not due to changes in TGF-β or IL-10 production but was associated with decreased T regulatory cell FOXP3 expression. In conclusion, our data provide one explanation for adjuvant properties of lenalidomide and pomalidomide and suggest that they may help overcome an important barrier to tumour-specific immunity in cancer patients. [ABSTRACT FROM AUTHOR]

Abstract: The thalidomide analogue and immunomodulatory drug (IMiD®) lenalidomide (CC-5013, REVLIMID™) is emerging as a useful treatment for a number of cancers and has recently entered phase III trials for multiple myeloma. It has been suggested that the anti-tumor effect of lenalidomide is related to its anti-angiogenic potency. In this regard, we have previously shown that lenalidomide inhibits angiogenesis in both rat and human in vitro models but does not affect endothelial cell proliferation. We now show that oral administration of lenalidomide attenuates growth factor-induced angiogenesis in vivo; the rat mesenteric window assay was utilized to show that lenalidomide significantly inhibits vascularization in a dose-dependent manner. We also found that lenalidomide significantly inhibits growth factor-induced endothelial cell migration. This correlates with the inhibitory effect of lenalidomide on growth factor-induced Akt phosphorylation, thereby providing a potential mechanism for its anti-migratory and subsequent anti-angiogenic effects. These data further support the use of lenalidomide as an orally administered drug for the effective treatment of angiogenesis-dependent conditions, including cancer, and suggest a potential mechanism of action. [Copyright &y& Elsevier]

Reliable quantitative evaluation of molecular pathways is critical for both drug discovery and treatment monitoring. We have modified the CAM assay to quantitatively measure vascular density, endothelial proliferation, and changes in protein expression in response to anti-angiogenic and pro-angiogenic agents. This improved CAM assay can correlate changes in vascular density with changes seen on a molecular level. We expect that these described modifications will result in a single in vivo assay system, which will improve the ability to investigate molecular mechanisms underlying the angiogenic response. [ABSTRACT FROM AUTHOR]