1.Hsa＿circRNA＿0000231 Suppress Breast Cacer Bone Metastasis Through MiR-135b-5p/ARHGAP12 Axis 2.Factors Associated With Bone Metastasis In Breast Cancer:a Meta-analysis

Breast cancer（BC）is the most common malignant tumor in women.The latest data in 2020 showed that there were up to 2.26 million women diagnosed BC in the world,which ranked first among all malignancies in cancer globally.In recent years,with the improvement of cancer awareness,the diagnosis rate of BC had been improved,and the treatment methods of BC were more comprehensive,which can significantly prolong the survival of patients with BC.However,postoperative follow-up was not timely,the diagnosis of BC with bone metastasis（BM）was not easy in the early stage,and the treatment was not effective.Once the occurrence of BC with BM,the quality of patients’life decreased,and a series of skeletal-related events（SREs）occur,and the survival time is significantly shortened.Currently,the main mechanism of BM focused on the RANK/RANKL/OPG signaling pathway.Although the treatment through RANKL-dependent pathways had shown significant efficacy,Denosumab still fails in some special patients.We need to find new effective therapeutic targets to inhibit bone destruction in BC patients.In this study,the molecular mechanism of BM from BC will be taken as the breakthrough point to find new targets,so as to provide a new treatment direction for BC with BM.Circular RNA（circRNA）is a cyclic structure formed by a series of transcription processes of single-stranded RNA.As a non-coding long-chain RNA,circ RNA has been proved to be a potential regulator of other RNAs.CircRNA can influence cell process and plays a key role from cell development to tumor growth.Now,as the star molecule,circRNAs have been increasingly studied in the field of cancer.CircRNA can participate in the invasion and metastasis of breast cancer.Because of its special closed-loop structure,it can stably exist in the cytoplasm without degradation,and it has disease specificity.Therefore,circRNA can be used as a biomarker for early diagnosis and prognosis evaluation in cancer,elucidate the specific mechanism of tumor occurrence and progress,and provide a new effective targeted therapy.In this study,circRNA high-throughput sequencing was performed on breast cancer cell MDA-MB-231 and high bone metastatic 231-B cells.There were 379 differentially expressed circRNAs,including 356 up-regulated circRNAs and 23 down-regulated ones.The significantly differentially expressed circRNAs were compared through literature retrieval,and the downstream target miRNAs and genes were predicted by biological information analysis.Quantitative Real time-PCR（qRT-PCR）was used to verify its expression level in tissue samples of BM from BC.In this study,hsa_circRNA₀000231—miR-135b-5p-ARHGAP12 axis was confirmed,and hsa_circRNA₀000231 was highly expressed in BM samples than the normal bone tissue.A series of in vitro functional experiments confirmed that knocking down the hsa_circRNA₀000231 can promote the expression level of miR-135b-5p,which can regulate the expression level of ARHGAP12 and inhibit the migration and metastasis of BC cells without affecting the proliferation of BC cells.When the expression of hsa_circRNA₀000231 is high in BC patients,there is still a possibility of BM,even if the tumor size is not large enough.In conclusion,this study fully confirmed the high expression of hsa_circRNA₀000231 in BM tissue through qRT-PCR,which has potential value as a biomarker for BC with BM in early stage,and is helpful early diagnosis and early intervention treatment.In addition,a series of in vitro experiments also strongly confirmed that hsa_circRNA₀000231 can promote the migration and metastasis without affecting the proliferation of BC cells.Finally,this study proposed the mechanism of ARHGAP12 in BC with BM for the first time,and further experiments will verify that ARHGAP12 specifically regulates RhoA and RAC1 homeostasis,promotes the mechanism of BM,and provides a new target for the precise treatment of BC with BM.Background:To systematically evaluate and analyze the risk factors for breast cancer（BC）with bone metastasis（BM）and provide clinical evidence supporting the early prevention of BM.Methods:We systematically retrieved databases from the Cochrane Library,PubMed,Web of Science,and EMBASE for BC with BM patient.Limited:Publication between January 1,2001,and December 31,2019.Literature screening and evaluation were performed independently by 2 evaluators.The quality of the included studies was evaluated with the NOS.Studies with NOS>6 on factors related to the BM of BC were identified.Weighted odds ratio（OR）were used as the combined effects.Results:We identified 18 articles with available data from 11 retrospective studies and 7 cross-sectional studies.In 11 retrospective studies,the NOS scores ranged from 6-9,including 3 studies scoring 6 points,2 studies scoring 7 points,4 studies scoring 8 points,and 2 studies scoring 9 points.In 7 cross-sectional studies,the AHRQ scores ranged from 6-9,including 3 studies scoring 8 points,3 studies scoring 9 points,and 1 study scoring 10 points.Progesterone receptor（PR）-positive BC patients had a relatively lower risk of BM（I2=45.9%,OR=0.80,95%confidence interval（CI）:0.72,0.88,p<0.001）.HER2-positive BC patients had a relatively higher risk of BM（I2=80.0%,OR=1.36,95%CI:1.04,1.79,p=0.025）.The risk of BM in patients with lymph node metastasis was higher than that in patients with no lymph node metastasis（I2=99.7%,OR=2.60,95%CI:1.41,4.80,p=0.002）.The risk of BM in stage T2 BC patients was 1.99 times that in stage T1 BC patients（I2=96.8%,OR=1.99,95%Cl:1.03,3.83,p=0.040）.The pooled data from 4 studies showed that the risk of BM in stage T3 BC patients was 4.74 times that in stage T1 BC patients（I2=95.6%,OR=4.74,95%CI:9.90,11.73,p=0.001）.The pooled data from 3 studies showed that the risk of BM in stage T4 BC patients was 14.57 times that in stage T1 BC patients（I2=95.4%,OR=14.57,95%CI:4.16,51.05,p<0.001）.The incidence of BM in BC patients without lobular or ductal BC was significantly higher than that in patients with ductal BC（I2=56.4%,OR=1.26,95%CI:1.09,1.45,p=0.001）.Conclusions:Patients with PR-positive BC have a relatively lower risk of BM.Patients with HER2-positive,lymph node metastasis-positive,nonlobular,or ductal BC have a relatively higher risk of BM.With increasing T stage,the risk of BM in BC patients also increases.