AIMS: Antitumour effects of pentapeptide (LH) derived from donkey serum albumin hydrolysates were tested against tumour cells both in vitro and in vivo. The mechanism of LH induced tumour cell apoptosis was investigated. MAIN METHODS: Human promyelocytic leukaemia cells (HL 60) were cultured to observe inhibition in vitro. Two animal models, a solid tumour and a non-entity myeloid leukaemia tumour, were used to determine the effect of LH in vivo. The former, fifty BALB/c nude mice were transplanted with HL 60 cells. The tumours were isolated completely and weighed after treatment. The latter, fifty BALB/c mice were injected intravenously with transplantable erythroblastic leukaemia cells (EL9611 cells). The survival time of mice was recorded and organs were used for histological study. The mechanism about tumour cell apoptosis was evaluated using fluorescence-activated cell sorting and transmission electron microscope for morphological assays. KEY FINDINGS: The LH inhibited tumour cell proliferation and the inhibitions were dependent on both the concentration and the dose; the best inhibition rate was up to 70% of the untreated control in vitro. It markedly inhibited the growth of a transplanted tumour with HL 60 cells in an immune-deficient nude mouse model. LH was also able to prolong the survival time of leukaemia mice with transplanted EL9611 cells and prevent the infiltration of leukaemia cells to the main internal organs. SIGNIFICANCE: The LH peptide is an excellent inhibitor of tumour cell growth. These data provide the experimental foundation to use the LH peptide as a candidate for antitumour drugs in the future.
AIMS: Antitumour effects of pentapeptide (LH) derived from donkey serum albumin hydrolysates were tested against tumour cells both in vitro and in vivo. The mechanism of LH induced tumour cell apoptosis was investigated. MAIN METHODS:Human promyelocytic leukaemia cells (HL 60) were cultured to observe inhibition in vitro. Two animal models, a solid tumour and a non-entity myeloid leukaemia tumour, were used to determine the effect of LH in vivo. The former, fifty BALB/c nude mice were transplanted with HL 60 cells. The tumours were isolated completely and weighed after treatment. The latter, fifty BALB/c mice were injected intravenously with transplantable erythroblastic leukaemia cells (EL9611 cells). The survival time of mice was recorded and organs were used for histological study. The mechanism about tumour cell apoptosis was evaluated using fluorescence-activated cell sorting and transmission electron microscope for morphological assays. KEY FINDINGS: The LH inhibited tumour cell proliferation and the inhibitions were dependent on both the concentration and the dose; the best inhibition rate was up to 70% of the untreated control in vitro. It markedly inhibited the growth of a transplanted tumour with HL 60 cells in an immune-deficient nude mouse model. LH was also able to prolong the survival time of leukaemiamice with transplanted EL9611 cells and prevent the infiltration of leukaemia cells to the main internal organs. SIGNIFICANCE: The LH peptide is an excellent inhibitor of tumour cell growth. These data provide the experimental foundation to use the LH peptide as a candidate for antitumour drugs in the future.