The Effect Of LipoxinA4 On Malignant Melanoma Growth In Nude Mice

To investigate the effect of LipoxinA4 on the growth of malignant melanoma in vivo.A375 cells were injected into the right axilla of the BALB/c-nu/nu female mice,mice were treated until the size of the tumors more than 5mm after inoculation.They were randomly assigned to 2 groups:(a)BML-111 group(intratumoral injected with BML-111,final dosage of 1 mg/kg);(b)control group(intratumoral injected with The same volumes PBS);The injection was performed daily for 8 days and every other day for the last 4 days.The general conditions of mice including activity and weight were observed daily.The size of the tumors was determined by caliper,measuring length(L)and width(W)of tumors 3 days a time.Tumor volumes(V)were calculated by the formula: V = L × W~2 ×0.5.The tumor growth inhibition rate was calculated by the formula: inhibition(%)=(1-tumor weight of BML-111group/tumor weight of control group)× 100%.Mice were weighed and sacrificed when the experiment was finished.The tumor tissues were surgically excised,weighed,and then fixed in 10%neutral-buffered formalin for histological examination,embedded in paraffin and cut into 4 mm sections.Sections were stained with hematoxylin and eosin for conventional morphologic evaluation under light microscope.For immunohistologic assay,VEGF expression was detected by anti-VEGF,primary antibodies,secondary antibodies were all conjugated to horseradish peroxidase.Blood were drawn from the orbital venous plexus,samples were incubated in an upright position at room temperature for 30 to 45 minutes to allow clotting.Serum was separated by centrifuge at 2,000 g for 15 minutes at 4?.VEGF protein levels in serum were measured through ELISA kits according to the manufacturer's instruction.Tumor growth speed was more slowly in BML-111 group than PBS group,the tumor volumes of BML-111 group were significantly smaller compared with PBS group,the tumors of BML-111 group were significantly smaller compared with PBS group,the tumor weight in BML-111 group were relative lower.Its inhibition rate was as high as 57.12%.At surgery,tumors in PBS group appeared less circumscribed,more extensively invading adjacent tissue,and more difficult to be dissected.Histological examination showed that PBS group no or little tumor necrosis displayed in tumors.However,BML-111 group showed visible responses with homogeneous necrosisthat was distinguishable in morphology from the PBS groups.VEGF expression in tumor tissue was studied by immunohistochemical staining.VEGF expression significantly decreased in BML-111 group than PBS group.We further evaluated the influence of BML-111 on serum VEGF protein levels in mice through ELISA kits.Serum VEGF in PBS group reached 20.57±0.41 ng/ml.However,VEGF concentrations substantially decreased to 7.87±0.28 ng/ml.in BML-111 group.The results suggesting that LXA4 suppresses the growth of malignant melanoma tumor in mice,and the anti-tumor effect maybe through inhibiting tumor-related angiogenesis.