Quantitative Study Of Breast Cancer Cell Migration Heterogeneity Based On Cell Motility

Cancer is one of the major diseases that seriously threaten human health.The main cause of death of cancer patients is cancer metastasis.Tumor metastasis is the process of tumor cells from the primary site to distant organs.Tumor cells fall off from the primary site,infiltrate into surrounding tissues,and spread to other tissues and organs in the body through the lymphatic system and blood system,forming metastatic lesions and increasing the mortality rate of patients.And all the processes of cancer metastasis are related to the movement of cancer cells.If you can stop the movement of cancer cells,you can stop the invasion and metastasis of cancer.Other studies have suggested that successful treatment of cancer depends in large part on the ability to inhibit the metastasis of tumor cells during metastasis.Therefore,controlling the movement of tumor cells has become one of the key issues in research.To date,cancer treatments have focused on preventing initial metastasis,narrowing established lesions,and preventing additional metastases in patients with limited disease,in order to extend cancer patients’lives and improve their quality of life.In terms of inhibiting tumor cell metastasis,it is suggested that the treatment of solid cancer should be supplemented by drugs to inhibit the invasion of cancer cells by extracellular matrix（ECM）and the formation of secondary tumors.The heterogeneity of tumors makes the cell migration ability different,which makes the development of tumor drug resistance and increases the difficulty of cancer treatment.Therefore,the quantitative study of tumor cell movement is particularly important to control tumor metastasis.Although the traditional two-dimensional in vitro studies of tumors and the observation of tumor cell movement in vivo have made significant progress,the two-dimensional in vitro studies cannot simulate the actual three-dimensional environment of tumor cells and the complex and uncontrollable environment of animals,which limits the development of related tumor research.Therefore,the establishment of a three-dimensional tumor microenvironment in vitro to study cell migration behavior has developed rapidly.The purpose of this study is to develop a method of constructing a three-dimensional environment of cell movement in vitro,quantifying and comparing cell movement behavior,and differentiating cell subsets according to cell activity,which is helpful for the development and application of drugs to inhibit tumor movement in clinical practice.The main work of this study includes the following aspects:（1）In vitro construction of cell motion microenvironment by microfluidic chip:polydimethylsiloxane（PDMS）was used as chip material,and silicon etching technology was used to etch chip template.Main component of extracellular matrix of collagen,typeⅠrat tail collagen hydrogel was used to simulate the extracellular matrix of tumor microenvironment,three-dimensional network structure of tumor cell movement in vitro microenvironment.（2）In vitro comparison of cell migration and invasion ability:human breast cancer cell lines with high invasion potential MDA-MB-231 and low invasion potential MCF-7were selected,and cell movement data were obtained by combining in vitro three-dimensional cell culture technology and single cell tracking technology.Based on the movement parameters of cells,such as trajectory,Mean Square Displacement（MSD）,velocity,direction autocorrelation function,velocity auto-covariance function and power spectrum.By comparing the average parameters of cell movement and analyzing the characteristics of cell overall movement,the migration and invasion abilities of different cells were compared rapidly（several hours）.（3）Quantitative analysis of tumor migration heterogeneity:based on the fitting of cell velocity auto-covariance,the movement characteristics of individual cells were analyzed.It was found that there were two modes of movement in both the high-invasion potential MDA-MB-231 cell line and the low-invasion potential MCF-7 cell line.In addition,it was also found that the activity of the two modes of cell movement was different.By the two modes of cell movement,the cells were divided into two subgroups with different motility.The ratio of active cells(₍（6（8））was given as a reference index for the heterogeneity of tumor cell migration.Through this method,different active cells can be selected,which can provide a platform for drug research and development to inhibit tumor cell migration,or provide new ideas for cell sorting,so as to promote the development of cancer treatment.