Life-Protecting Factor (LPF): An anti-cancer low molecular weight fractionisolated from pregnant uterine mucosa during embryo organogenesis

It is clear from literature that pregnant uteri extracts taken from C57BL/6 syngeneic mice during embryonic differentiation inhibit significantly Lewi s tumor growth in vivo. We examined in this study the effects of mouse whol e uterus and pig crude uterine mucosa extracts at early days of pregnancy o n the growth of different human tumor cell lines in vitro. In addition, we examined the cell proliferation curves of some of the above lines after the treatment with a 10 kDa fraction of mouse and pig pregnant uterine mucosa extracts. We recorded a significant inhibition of the cell proliferation cu rves of all treated tumor cell lines. This inhibition was also evident afte r the treatment with the cut-off fractions. HPLC analysis of the 10 kDa fra ction showed the presence of 4 peptides, 3 of which having a molecular weig ht ranging between 5 kDa and 10 kDa, and the fourth being lower than 5 kDa. The 5 kDa fraction inhibited the cell proliferation curves as well as the crude pregnant uterus extracts. We named this low-MW fraction "Life-Protect ing Factor".