Anticancer Effect And Mechanism Of L-proline-m-bis (2-chloroethyl) Amino-L-phenylalanyl-L-norvaline Ethyl Ester Hydrochloride (MF13) In Human Hepatocellular Carcinoma: In Vitro And In Vivo

L-proline-m-bis (2-chloroethyl) amino-L-phenylalanyl-L-norvaline ethyl ester hydrochloride (MF13) is a new anticancer tripeptide with molecular weight of 566. MF13 showed antiproliferative activities in the panel of 7 human hepatocellular carcinoma (HCC) cell lines with IC50 and IC90 values in the range of 0.32~ 2.32μM and 3.84~29.20μM respectively. Data showed MF13 had a low toxicity and good selectivity to human HCC in respect to human lymphocytes and normal liver cells which were used as normal control cells. The data of pulse exposure experiment indicated that the uptake of MF13 was fast, with cell viability of being less than 50% after 2hrs of exposure.Cell cycle analysis showed a significant blockade in the S-phase by MF13 and over 75 percent of the tumor cells accumulated in the S-phase 24hrs after their exposure to MF13. Morphological examination as well as DNA gel electrophoresis demonstrated clearly a nuclear fragmentation and DNA degradation in the MF13 treated tumor cells. Bel-7402, HepG2 and QGY-7701 cells treated with MF13 for 48hrs revealed the similar apoptotic characteristics, such as condensation of cytoplasm and chromatin, fragmentation of nuclear into discreted masses. Bel-7402 cells treated with MF13 for 72hrs at 0.88 μM or higher exhibited a dose-dependent multiple-unit DNA ladder using agarose gel electrophoresis.Western Blot analysis displayed that the inactivated Rb (phosphorylated Rb, pRb), which is presented in the S-phase, was increased within 6hrs of MF13 treatment. Bcl-2 expression was without change in HCC cells treated with MF13, however, a significant increase of Bax (Bax expression has shown a time-dependent and dose-dependent pattern) was observed, resulting in a decreased ratio of Bcl-2/Bax. Bax also increased in other types of tumor cells such...