The Relationship Between Abnormality Of Gastric Cancer Cell Cycle And The Signal Transduction Mediated By Transforming Growth Factor-Beta

Aims:Through the recently studies,we know that tumor is inducded by abnormality of cell division and growth,also is a kind of cell cycle disease.What causes the the abnormality of cell cycle,the signal transduction in cell has been a biological question that people pay close attention to.The signal transduction in cell regulates the growth,development,division and decease of organisma multicellularis,It also has close relationshrp with the occurrence and development of malignant tumors.We find that there are many routes of the signal transduction in cell,the The TGF-βpathway mediated by the SMAD is a important one of them.we wili study the relationship betweenit and the abnormality of gastric cancer cell cycle.Methods;We investgated 61 cases with gastric cancer,39 cases served as normal controls.Their clinical index was noted.The sample was taken,washed clean by NS,then placed in liquid nitrogen。The levels of TGF-βmRNA,TβRâ…¡mRNA and Smad4mRNA in gastric cancer tissue were tested by the reverse transcription-polymerase chain reaction assay method.Gastric cancer cell cycle was tested by FCM(flow cytometry)and analyzed by multicycle software.The statistical analyses adopted Pearson chi square test,Leneve's test and linear correlation of SPSS11.0 statistical software.Results:There is significant deviation between the expressions of TGF-β,TβRâ…¡,Smad4 in gastric mucosa and gastric cancer tissue.TGF-βexpresses high in gastric cancer tissue but TβRâ…¡and Smad4 in normal gastric mucosa.The expressions of TGF-β,TβRâ…¡,Smad4 have no relationship with age, sexuality,loction and size of tumor(P＞0.05)but have relationship with the differentiation,infiltration,lymphatic metastasis and TNM stage of tumor(P＜0.05).In tumor that well—differentiated,infiltrated superficial,with no lymphatic metastasis and onâ… orâ…¡stage of TNM,TGF-βexspresses high but TβRâ…¡,Smad4 exspresses low.The relationship of TGF-βand TβRâ…¡is inverse correlation (x²=22.06,P＜0.05),so the TGF-βand Smad4(x²=17.09,P＜0.05).but it is direct correlation between TβRâ…¡and Smad4(x²=5.79,P＜0.05)。We find no cell cycle abnormality in controls,but 5 in 33 well—differentiated gastric cancer,and 13 in 28 poorly- differentiated gastric cancer(X²=7.124,P＜0.05).TGF-β,TβRâ…¡have no relationship with index of cell multiplication,but DPC4 has inverse correlation with SPF,PI and G₂M(r_SPF=-0.306,r_PI=-0.285,,r_G2M=-0.287;P＜0.05),has direct correlation with G_0/1(r_G0/1=0.313,P＜0.05).Conclusions:There is significant deviation between the expressions of TGF-β,TβRâ…¡,Smad4 in gastric mucosa and gastric cancer tissue.In gastric cancer tissue,the relationship of TGF-βand TβRâ…¡is inverse correlation,so the TGF-βand Smad4.but it is direct correlation between TβRâ…¡and Smad4.TGF-β,TβRâ…¡and Smad4 have relationship with the genesis,differentiation,metastasision of tumor.They can inhibite gastric cancer on initial stage,but promote it develoed on progression.TGF-β,TβRâ…¡have no relationship with index of cell multiplication,but DPC4 has inverse correlation with SPF,PI and G₂M,has direct correlation with G_0/1.It possible means that with the degrade of Smad4,body gradually loses the control of cell multiplication,and this induces cancer.