| Breast cancer is one of the most common cancers among women,and its morbidity is the first in Chinese urban female cancer.It is the leading killer of female life and health.The number of breast cancer cases is expected to reach 234,000 by 2030,up 31.15% from 2008 in China.Hyaluronan(HA)is the main component of extracellular matrix(ECM),which is directly related to the poor prognosis of breast cancer patients.Hyaluronan(HA),a polymer with various molecular weights(MW)found in tumor microenvironments,is associated with malignant progression of breast cancer.Reducing the amount of high-MW HA in the microenvironment by hyaluronidase is a promising approach for breast cancer treatment.However,whether the generation of HA fragments negatively affects breast cancer cells remains to be determined.Furthermore,HA forms three dimensional(3D)networks by cross-linking with other extracellular molecules to function.Therefore,a model mimicking the cross-linked HA network is required to determine the effect of HA fragments on breast cancer cells.In rodents,the naked mole rat(nmr)has long life span and is antagonistic to tumor.The naked mole rat is cancer resistant due to the abundant production of extremely high-molecular-weight hyaluronan(EHMW-HA).However,whether this special biopolymer has similar anti-cancer effects in mice and humans remains to be determined.Therefore,the establishment of research system of different molecular weight HA interact with breast cancer cells and the exploration of molecular mechanism of different molecular weight of HA in human breast cancer progress,is helpful to improve breast cancer treatment strategy.In this study,a 3D culture system was set up by covalently cross-linking HA with alginate and investigating the behavior of 4T1 and SKBR3 breast cancer cells alongside a two-dimensional(2D)control.The results show the invasion and migration abilities of 4T1 and SKBR3 cells are significantly enhanced by the presence of HA35 but inhibited by HA117 in both 2D monolayers and 3D spheroids.The differential effects of HA35 and HA117 on cancer cell epithelial-mesenchymal transition(EMT)phenotype were further confirmed in terms of differential regulation of E-cadherin and Vimentin as important EMT markers at both the cellular and m RNA levels.An in-depth exploration of molecular mechanisms show the CD44-Twist signaling pathway might be involved in the differential effects of HA35 and HA117.Furthermore,the present study used mouse 4T1 and human BT549 breast cancer cell lines to clarify the effect of EHMW-HA on breast cancer.First,overexpression of nmr HAS2 in 4T1 and BT549 cell lines in both 2D and 3D models was established.The 4T1-nmr HAS2 and BT549-nmr HAS2 cells could secrete EHMW-HA(molecular weight up to 6 MDa),similar to that found in the naked mole rat.Second,EHMW-HA significantly enhanced apoptosis,inhibiting the proliferation of 4T1 and BT549 cells in both 2D monolayers and 3D spheroids.The prominent anticancer effects of EHMW-HA on cancer cell apoptosis phenotype were further confirmed by inhibiting tumor formation in nude mice.Finally,we found that EHMW-HA resulted in different anticancer mechanisms in mouse and human cells.EHMW-HA significantly induced higher p53 protein expression,which enhanced pro-apoptotic proteins p21 and bax and modulated their functions in breast cancer cells.All in all,this study investigates the influence of different molecular weight HA on the invasion,proliferation and apoptosis of breast cancer cells.It shows that different molecular weight HA has different biological functions in regulating the behavior of breast cancer cells.These results have important implications with respect to understanding the role of HA in breast cancer development and for the design of therapeutic approaches based on the eradication of HA with hyaluronidase and the application of EHMW-HA. |
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