BACKGROUND:The extracellular matrix is a complex network structure,which not only builds physical support for tissue cells,but also plays an important regulatory role in cell survival,proliferation,and death.Abnormal changes in the biochemical and biomechanical properties of the extracellular matrix can significantly affect the proliferation,migration,immune evasion,and treatment resistance of tumor cells.Stiffness is an important mechanical property of the extracellular matrix,and abnormalities in matrix stiffness are closely related to tumor progression.OBJECTIVE:By reviewing the mechanism of extracellular matrix sclerosis,the impact of high stiffness matrix on tumor progression,and the latest research progress in the treatment of cancer based on reducing matrix stiffness,to deeply understand the mechanical properties of the extracellular matrix,improve the understanding of the complex mechanism of tumor progression,and provide new ideas and directions for tumor treatment.METHODS:"Extracellular matrix function,extracellular matrix stiffness,collagen deposition cross-linking,extracellular matrix stiffness therapy,immunotherapy"were used as the search terms in Chinese and English.Relevant literature published from January 2016 to June 2024 was searched in CNKI,PubMed,and WanFang databases,and 80 articles were finally included for review.RESULTS AND CONCLUSION:(1)Deposition and excessive cross-linking of collagen and elastin in the extracellular matrix leads to matrix remodeling,which in turn increases matrix stiffness.This sclerosis activates pro-cancer signaling pathways such as cyclin-D1,Rho/ROCK,p-PXN-Rac1-YAP,and STAT3/p-STAT3,promotes malignant behaviors such as cancer cell proliferation,metastasis,tumor microangiogenesis and immune escape,and accelerates tumor progression.(2)Reducing the deposition and cross-linking of matrix proteins can reduce matrix stiffness,which cannot only inhibit the activation of multiple cancer-promoting signaling pathways,but also enhance the penetration and delivery of drugs at tumor sites,which is a new strategy for cancer treatment.(3)At present,drugs based on matrix degradation to reduce tumor stiffness are under development,and a few drugs have entered the clinical trial stage,which are expected to provide a new powerful weapon for tumor treatment.

BACKGROUND:The extracellular matrix is a complex network structure,which not only builds physical support for tissue cells,but also plays an important regulatory role in cell survival,proliferation,and death.Abnormal changes in the biochemical and biomechanical properties of the extracellular matrix can significantly affect the proliferation,migration,immune evasion,and treatment resistance of tumor cells.Stiffness is an important mechanical property of the extracellular matrix,and abnormalities in matrix stiffness are closely related to tumor progression.OBJECTIVE:By reviewing the mechanism of extracellular matrix sclerosis,the impact of high stiffness matrix on tumor progression,and the latest research progress in the treatment of cancer based on reducing matrix stiffness,to deeply understand the mechanical properties of the extracellular matrix,improve the understanding of the complex mechanism of tumor progression,and provide new ideas and directions for tumor treatment.METHODS:"Extracellular matrix function,extracellular matrix stiffness,collagen deposition cross-linking,extracellular matrix stiffness therapy,immunotherapy"were used as the search terms in Chinese and English.Relevant literature published from January 2016 to June 2024 was searched in CNKI,PubMed,and WanFang databases,and 80 articles were finally included for review.RESULTS AND CONCLUSION:(1)Deposition and excessive cross-linking of collagen and elastin in the extracellular matrix leads to matrix remodeling,which in turn increases matrix stiffness.This sclerosis activates pro-cancer signaling pathways such as cyclin-D1,Rho/ROCK,p-PXN-Rac1-YAP,and STAT3/p-STAT3,promotes malignant behaviors such as cancer cell proliferation,metastasis,tumor microangiogenesis and immune escape,and accelerates tumor progression.(2)Reducing the deposition and cross-linking of matrix proteins can reduce matrix stiffness,which cannot only inhibit the activation of multiple cancer-promoting signaling pathways,but also enhance the penetration and delivery of drugs at tumor sites,which is a new strategy for cancer treatment.(3)At present,drugs based on matrix degradation to reduce tumor stiffness are under development,and a few drugs have entered the clinical trial stage,which are expected to provide a new powerful weapon for tumor treatment.

Objective · To observe the micro-structure changes in rat tooth movement process under different force values through Micro-CT dynamic observation. Methods · Fifteen SD adult male rats at the age of 8 weeks were divided into three groups randomly (n=5), with the left maxillary as the experimental side and the nickel titanium coil springs, fixed between the first molar and incisor where thrust augmentation was conducted respectively by 20, 50 and 100 gf (1gf=0.0098 N) for continuous 14 d to it. Rat scanning in vivo through Micro-CT was carried out at day 0, 3, 7, 10 and 14 after force values were loaded on. The root resorption crater volumes and structure parameters for bone trabecula at different time points were measured. Results · Three days after thrust augmentation was conducted, root resorption crater volume for each group had a slight increase and an obvious increase occurred from the 3rd day to the 10th day, and then a slow increase happened 10 d later; from the 7th day to the 14th day, root resorption crater volume for 100 gf stress group was obviously greater than those of the other groups with statistical differences (P<0.05). With time for thrust augmentation passing by, bone volume fraction at the pressure side of alveolar bone decreased gradually and bone trabecula morphology became tiny and exiguous; besides, bone trabecula gap became narrow first and broad afterwards, and trabeculae trended to change from clintheriform to rhabditiform. Furthermore, alveolar bone resorption occurred in each stress group with consistent tendency. Conclusion · Different orthodontic force values all can cause root resorption, which experiences lag phase, rapid phase and stationary phase. Over-loaded orthodontic force induces more root resorption. During the process of the tooth movement, the pressure side of alveolar bones appears reconstruction and absorption, whose variation is not related with force degree.