Inhibiting tyrosine kinases has recently emerged as a therapeutic modality in several forms of neoplasia. The tyrosine kinase inhibitor STI571 (IMATINIB MESYLATE; GLEEVEC; GLIVEC) is a case in point as it has shown promise in the treatment of malignancies expressing the BCR/ABL fusion protein. In addition to BCR/ABL, STI571 inhibits the tyrosine kinase moieties of several cell surface receptors including the platelet-derived growth factor (PDGF) receptors and c-Kit. Previous work demonstrated that c-Kit activation supports migration, invasion and, survival of certain colorectal carcinoma cells including DLD-1. Here we describe that blocking c-Kit with STI571 inhibits these malignant traits not only in DLD-1 cells but also in two early passage colorectal carcinoma cell strains. Specifically, STI571 inhibited anchorage-independent colony formation and cell scattering in semi-solid medium. Furthermore, it enhanced apoptosis susceptibility and abrogated invasion of DLD-1 cells through Matrigel. In addition, STI571 treatment affected the balance of the Bcl-2 family of apoptosis regulators on favor of a pro-apoptotic phenotype. Specifically, STI571 treatment of DLD-1 cells was associated with lower levels of Bcl-2 expression accompanied by de novo expression of Bcl-xS. Finally, STI571 acted as a chemosensitizing agent in DLD-1 cells when used in combination with 5-fluorouracil.

Abstract. The precise timing of the angiogenic switch in colorectal cancer development is still unclear. The simultaneous expression of Endoglin (CD105), transforming growth factor (TGF)-ß1 and TGF-ß receptor (R) II were quantified in surgical specimens comprising normal human colon, pre-malignant dysplastic tissue, in situ, and invasive colon cancer specimens, at mRNA and protein levels, respectively by real-time PCR and immunohistochemistry. Serum concentrations of soluble Endoglin and TGF-ß1 were evaluated. mRNA and CD105 + -microvessel density (MVD) increased significantly in dysplastic colon and carcinoma versus normal tissues; values correlated respectively with dysplasia degree and Dukes' stages. TGF-ß1 expression was significantly upregulated in most severe dysplastic adenoma specimens, while TGF-ß1 transcript and protein signals were intense in carcinoma, positively-correlated with tumor progression. TGF-ß1 RII was overexpressed in adenoma and carcinoma versus normal samples, but unrelated with dysplasia or Dukes' stage. Soluble Endoglin serum levels were equivalent in adenoma and normal tissues; in carcinoma the highest levels were in invasive tumor. Circulating TGF-ß1 levels were increased in severe dysplasia and progressed with tumor progression. Correlations between adenoma dysplasia degree and TGF-ß RII and CD105 + -MVD, and between tumor Dukes' staging and TGF-ß1 and CD105 + -MVD, were significant. TGF-ß1 and Endoglin and TGF-ß1 serum levels, TGF-ß1 staining and CD105 + -MVD were significantly and inversely associated with disease-free survival. TGF-ß1 levels were an independent and significant prognostic factor of disease-free survival. These findings suggest active angiogenesis occurs in many pre-malignant colon cases and supports more careful evaluation of different chemopreventive agents.

No abstract

No abstract

Objectives ‐ The purpose of this study was to analyse the presence of the granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) in human cerebrospinal fluid (SF) of patients affected by multiple sclerosis (MS) in comparison with non‐inflammatory neurological diseases. Material and methods ‐ All SFs were collected from 59 patients for diagnostic purpose. The presence of GM‐CSF was revealed by measuring its activity and by immunoassay. The data obtained were statistically evaluated. Results ‐ We found that GM‐CSF is constitutively present in human SF; this presence was confirmed by its stimulating activity of colony‐forming‐unit granulocyte‐macrophage (CFU‐GM) production. No significant changes of the GM‐CSF concentration in the SFs were observed among different neurological disorders (degenerative or vascular) and MS. Conclusion ‐ Our data suggest that GM‐CSF is a constitutive component of human SF, relatively uninfluenced by the different morbid conditions of the nervous system.