The Effect Of Kisspeptin-10 On Bone Metastasis And Bone Destruction In Breast Cancer And The Mechanism

Background and objectivesBreast cancer is the second most common malignant tumor in the world.It ranks the first in female malignancy,and the morbidity is rising in recent years.The most common metastatic site of breast cancer is bone,breast cancer patients with bone metastases in the late suffer bone pain,pathological fractures,nerve compression and other bone related symptoms,seriously affecting the quality of life and prognosis.Bone metastasis of breast cancer is a complex process,there is no effective of drug therapy for breast cancer bone metastasis until now.Finding a target to prevent and treat bone metastasis of breast cancer becomes the primary task of tumor therapy.In 1996,KISS1 gene was found as a tumor suppressor gene in malignant melanoma cells by Lee JH,etc.In 1997,Lee JH,etc.reported the suppression fuction in human breast carcinoma MDA-MB-435 cells after transfection with KiSS-1.The KISS1 gene encodes a peptides containing 145 amino acids,which can be hydrolyzed to different lengths of peptide fragments,known as Kisspeptins,in which Kisspeptins-10 is the shortest with strongest activity.The receptor for Kisspeptins is termed GPR54.Like most G protein-coupled receptors,GPR54 consists of 398 amino acids,forming a seven transmembrane structure.GPCR is a successful drug target currently on the market.The mechanism study of KISS1/GPR54 in breast cancer bone metastasis may provide a target for the treatment of breast cancer bone metastases.Research contents and methodsIn our experiment,the bioinformatics analysis were carried out through the data obtained from the cancer genome atlas(TCGA)database of patients with breast cancer,we found that the expression of GPR54 was significantly increased in the Luminal breast cancer.We made a comparative and contrastive analysis of ER,PR,and Her2 in the breast cancer samples from TCGA database,and detected the expression of GPR54 in 118 clinical cases of primary breast cancer with immunohistochemiscal staining.The results indicate a strong positive correlation of ER and PR status and GPR54 expression.Meanwhile,the method of immunohistochemical staining was applied on the GPR54 of the breast cancer bone metastases and primary breast cancer specimens breast,respectively.The proportion of GPR54 high expression in breast cancer bone metastases specimens was much higher than in primary breast cancer specimens.The high expression of GPR54 indicates that the GPR54 may be a potential therapeutic target for breast cancer,especially for Luminal breast cancer bone metastases.The western blot in different breast cancer cells indicated that the GPR54 was highly expressed in BT474 cells,so the BT474 cells were selected for the further cell and animal experiments.In Transwell cell migration experiments,KP-10 has a significant effect on the migration of BT474 cells.The differentiation of osteoclast research suggests that Kp-10 induces the cell differentiation.In vitro cell culture,KP-10 with different concentrations were employed to study the effects of cooperative gene,and the result show that KP-10 has a promotion effect on the expression of cooperative gene OPN,MMP1,CTGF,IL-11 and RANKL.Then the animal experiments were carried out by injecting BT474 cells into mice' left ventricle and tibia.Different concentrations of Kp-10 are injected through tail vain.The bioluminescent analysis,X-ray pictures of tibia and three-dimensional Micro CT reconstruction were used,and the results show that Kp-10 has a stimulating effect on the bone metastases and destruction of BT474.Results and conclusionThese experimental results indicate that the GPR54 is highly expressed in BT474 cells,and which has a positive correlation between the expression of GPR54 and ER and PR positive.Our experiments confirmed that the Kp-10 can promote the cell migration of BT474 and the differentiation of osteoclast caused by breast cancer cells,and Kp-10 has a positive impact on the expression of BT474 synergistic gene OPN,MMP1,CTGF,il-11 and RANKL.The animal experiments show that Kp-10 has a stimulating effect on the bone metastases and destruction of BT474,which has a potential application on the clinical treatment.These results suggested that the bone metastasis and destruction caused by Lumianl breast cancer might be treatable by controlling or adjusting the expression of KISS1 gene.