We have reported earlier a novel combination of four structurally designed synthetic
neuropeptide analogs of
vasoactive intestinal peptide (VIP),
bombesin,
substance P and
somatostatin, code-named
DRF 7295 which have anti-
tumor efficacy for
adenocarcinomas in vitro and in vivo (Jaggi et al., Invest New Drugs, 2008). The discovery, synthesis, in vitro and in vivo efficacy was reported (Jaggi et al., Invest New Drugs, 2008). Gastrointestinal
tumor cells of the colon, pancreas and duodenum were found to most sensitive to
DRF7295 in vitro and in vivo (Jaggi et al., Invest New Drugs, 2008). We have further investigated and report here the modulation of cellular signaling in gastrointestinal
carcinomas by
DRF 7295, which may be mediating its observed anticancer activity in these
cancer types.
DRF 7295 inhibits the binding of specific
neuropeptides initiating a cascade of cellular signaling events leading to programmed cell death. It down regulates the second messenger cAMP,
epidermal growth factor (
EGF) dependent proliferation and the phosphorylated MAP
Kinase pERK1/2 in gastrointestinal
carcinomas, thus depriving the tumour cells of critical pro-proliferative cellular signals. It triggers bcl2 and
Caspase 3 dependent apoptotic cell death and induces
p53 tumor suppressor protein in the treated
carcinoma cells in vitro. It has significant anti-angiogenic potential as reflected in the inhibition of tube like formation in the endothelial cells and down regulation of
VEGF levels. Tumour xenograft studies confirmed the in vivo efficacy of
DRF 7295 for gastrointestinal
carcinomas (Jaggi et al., Invest New Drugs, 2008). The Phase I clinical trials have shown
DRF 7295 to be well tolerated and devoid of systemic toxicities of the conventional cytotoxics (Mukherjee et al., Phase I dose escalating study of
DRF7295: a new class of
peptide based drugs. "Abstract" ASCO ID:948, 2003). The
drug may have a promising role in disease stabilization in colorectal and other
cancers. Thus
DRF 7295 is a novel targeted
drug in the class of signal transduction modulators, with potential for treatment of gastrointestinal
carcinomas.