Mechanism Of SIRT7 Negative Regulation Of TIE2 Mediated Adriamycin Inducing Breast Cancer Invasion And Matastasis

【Purpose】Chemotherapy is one of the commonly used treatment methods in clinical breast cancer patients.However,Chemotherapy may act as a double-edged sword: although chemotherapy kills cancer cells,it also contributes to chemo-resistance and metastasis based on our previous study.The main purpose of this project is to explore the effect of adriamycin on the invasion and metastasis of breast cancer cells and to identify key regulators of signaling pathways activated during adriamycin(ADR)treatment.【Methods】1.Cell proliferation assay,scratch healing experiment,transwell invasion assay were used to determine the effect of adriamycin on the proliferation and migration of breast cancer cells.Besides,quantitative real-time PCR and Western blot were used to access the mRNA and protein expression of the metastasis-related markers.2.The lung metastasis model of BALB/c nude mice was established,and the metastasis of adriamycin-sensitive cell MCF-7 and drug-resistant cell MCF-7/ADR was observed by imaging technology based on the data of pulmonary metastasis nodules and HE staining.3.High-throughput transcriptome sequencing was performed on MCF-7 and MCF-7/ADR.The differentially expressed genes were identified to explore the key genes and potential therapeutic targets that were related to adriamycin-induced metastasis.4.The time-dependent and concentration-dependent effects of ADR were determined.And the protein expression levels of deacetylase SIRT7 and tyrosine kinase receptor TIE2 was detected by Western Blot.And we determined the relationship between SIRT7 and TIE2 by overexpressing SIRT7 and knockdown TIE2 in breast cancer cells.5.The interaction between SIRT7 and TIE2 in breast cancer was analyzed by GEPIA databases and TIMER databases.And the difference in expression of SIRT7 and TIE2 in breast cancer patients was detected by Immunohistochemistry.6.The effects of SIRT7 and TIE2 on the migratory of breast cancer cells were determined by the scratch healing experiment and the transwell invasion experiment.And detect the effect of SIRT7 and TIE2 on the regulation of metastasis-related markers by Western blot.7.The effects of the activation of SIRT7 and the inhibition of TIE2 on breast cancer metastasis were further determined in vivo,The expression levels of SIRT7 and TIE2 were further detected by immunohistochemistry.【Results】1.Adriamycin can inhibit the proliferation of breast cancer cells,but it can also increase the migratory of breast cancer cells;adriamycin stimulation can upregulate the mRNA and protein levels of markers related to metastasis.2.Transcriptome sequencing results suggest that the ADR-induced metastasis might be related to the down-regulation of SIRT7 and the upregulation of TIE2.3.Western Blot results confirmed that adriamycin negatively regulates TIE2 by down-regulating SIRT7 and may promote the metastasis of breast cancer cells by activating the AKT pathway;the negative correlation between SIRT7 and TIE2 in breast cancer was further verified by GEPIA and TIMER databases.4.The expression level of SIRT7 in cancer tissues of breast cancer patients treated with adriamycin was down-regulated and had a negative correlation with TIE2.5.After overexpression of SIRT7 and knockdown of TIE2 in breast cancer cells respectively,the metastasis and invasion ability of breast cancer cells were weakened,and the expression level of protein markers associated with promoting metastasis was down-regulated.6.In the BALB/c nude mice lung metastasis model,the metastasis ability of the experimental group was weaker than that of the control group.Immunohistochemical results showed that resveratrol can down-regulate SIRT7 in breast cancer cells and cabozantinib can inhibit TIE2 in breast cancer cells.【Conclusion】1.Adriamycin not only can inhibit the proliferation of breast cancer cells but also may enhance the metastasis ability of breast cancer cells;2.SIRT7 may be a key molecule for adriamycin to promote breast cancer metastasis;3.SIRT7 may inhibit the occurrence of breast cancer metastasis by negatively regulating TIE2;4.Adriamycin therapy may induce breast cancer metastasis in a SIRT7/TIE2 axis dependent manner.