In the presence of M STI, HT cells underwent morphological changes and detached from the surface of the dish.In contrast, there was no significant Losartan effect on the cell cycle distribution profile in the presence of M STI. A, concentrationdependent inhibition of HT cell proliferation by STI.B, timedependent induction of HT cell apoptosis by STI. Data are the means SE of tumor measurements using micegroup and are representative of another experiment.There was no undesirable effect of STI treatment on animal behavior and body weight.A that ngml SCF promoted a remarkable stimulation of new vessel formation that was comparable with that induced by the proangiogenic factor VEGF. Control cells move from their initial uniform pattern of dispersed cell layers and associate to form a network of cell clusters connected by long, multicellular processes, leading to the formation of tubelike structures.Thus, we have demonstrated here the ability of human SCF to function as a proangiogenic factor through a direct interaction on endothelial cells.STI FOR COLORECTAL CANCER THERAPY human colon cancer cells cultured in the presence of serumassociated growth factors.Accordingly, several experimental studies indicate that HT cancer cells and human digestive tumors in general are controlled in vitro and in vivo by a complex network of autocrine and paracrine mitogenic loops involving transforming growth factor and other endogenous growth factors. Most interestingly, our data indicate that the growthsuppressive effect of STI is directly connected with its ability to induce programmed cell death in cultured HT cells.This cytotoxic effect is probably caused by the implication of the ckit receptor in cell survival and adhesion. In turn, it will be intriguing to determine whether the proapoptotic response induced by the ckit inhibitor STI in colon cancer cells can synergize with other apoptosisinducing agents or with anticancer drugs acting through other mechanisms, including cell cycle arrest or antiangiogenic responses.Most interestingly, we observed that SCF is a potent proangiogenic factor in vivo and in vitro.Thus, one can postulate that the ckit pathway and STI may exert a significant impact on the growth and dissemination of digestive tumors expressing ckit, after detection by systematic screening.In agreement with this proposition, we observed in the present model of HT xenografts in the nude mice that the pharmacological control of the ckit tyrosine kinase by STI resulted in a significant inhibition of tumor growth.The highly tumorigenic HT human colon cancer cell line was Dopamine hydrochloride previously selected as a pertinent predictive model for the identification of efficient combinations between chemotherapeutic agents for colorectal cancer therapy. Previous therapeutic strategies for advanced colorectal cancer were essentially limited to regimens using fluorouracil combined with folinic acid. More recently, combinations of fluorouracil with either CPT or oxaliplatin, according to different schedules, clearly improved the results in metastatic patients.Some of these combinations are now used in clinical trials for adjuvant colorectal cancer patients. The third step will undoubtedly be based on novel protocols using anticancer drugs targeting signaling molecules implicated in critical oncogenic pathways, alone or combined with conventional chemotherapy.For example, the epidermal growth factor receptor tyrosine kinase inhibitor ZD is now in clinical trials against colon cancer and other solid tumors.