Significance Of Expression Of TGFβ1, Smad2 And Smad4 In Hepatocellular Carcinoma Tissues

Hepatocellular carcinoma (HCC), one of the most frequent tumor worldwide, was wellknown for ite highly invasion, rapid growth, metastatic activity and poor prognosis. The emergence, devolepment and metastasis of HCC was a complex process. The TGFβ-Smad signaling pathway was an important pathway to induce emergence, devolpment and metastasis of HCC.In this pathway,TGFβ1 first bindsd to the type Ⅱreceptor,whith occurs in the cell membranes as a digmeric form,then the TGFβRⅠphosporylates TGFRβⅡin the GS domain to activate it.This activated the type kinase and teansiently associate with and phosphory lation of R-Smads (receptor-regulated Smads,such as Smad2 and Smad3).The phosphorylation of R-Smads resucts in formation of a heteromeric complex with another commin Smad (smad4) and translocates into the DNA-binding cofactors,activate specifical target genes.It can inhibit cell prolferation through triggered G1 periods interruption, promote cell to differentite,induce cell to apoptosis,and so on.The TGFβ-Smad signaling pathway will interrupt if one of factor inactive.So that it would led to emergence of HCC,and Smad4 is the easiest change in this pathway.It had tested that the interruption of TGFβ-Smad enhance the emergence of HCC. It was helpful in learning the relationship between TGFβ-Smad signaling pathway and emergence and development of HCC through study the TGFβ,Smad2and Smad4 in HCC.It also would provide some new methods of therapy. There was no report about the relationship among TGFβ,Smad2,Smad4 in HCC in our country. In the present study, the formalin-fixed specimens of 41 HCC patients , which were obtained from who underwent surgery , were routinely embedded in paraffin ,cut into sections, then their Smad2 mRNA and Smad4 mRNA were stained by in-situ hybridization technique, while the proteins of TGFβ1, AFP, Smad2, Smad4 were stained by immuohistochemistry method of avidin-biotin complex (ABC) respectively , to investigate the relationship between the TGFβ,Smad2,Smad4 and HCC and the relationship among the three factors. Materials and Methods Tissues of HCC were obtained from 41 patients who underwent surgery, including adjacent noncancer liver tissues (ANLT). There are 27 males and 14 females. The age of patients ranged from 29 to 67 years old (mean: 51.1years old). Tumors were graded according to the criteria described by Edmondson and Steiner, GradeⅠ, 7 samples; GradeⅡ, 8 samples; GradeⅢ,6 samples; Grade Ⅳ, 20samples. No patients had received radiotherapy, chemotherapy, immunotherapy or TECA before the surgery. A total of five cases of laceration injury of liver were used as controls. Using the monoclone antibodies of anti-TGFβ1 , anti -AFP and multiclone antibodies of Smad2 and Smad4 , immunohistochemical (ABC methods) stainings were proformed . While their Smad2 mRNA and Smad4 mRNA were stained by in-situ hybridization technique. The immunohistochemical and in-situ hybridizational stainings were assessed according to both the distribution (the percentage of positive cell) and the instensity of staining. Those having positive staining in less than 3 score were regarded as"--", greater than 3 score as "+". Staistical analysis was executed by SPSS 10.0 Software,P valus less than 0.05 were considered significant. Results 1. The expressions of Smad4 and Smad4 mRNA in normal control were both positive, while, AFP, TGF β1, Smad2 , Smad2 mRNA were all negative. 2. The positive rate of AFP, TGF β1, Smad2, Smad2 mRNA , Smad4 and Smad4 mRNA in HCC were respectively 70.7%(29/41), 75.6%(31/41), 43.9%(18/41), 61.0%(25/41), 48.4%(20/41), and 53.6%(22/41) . 3. The positive rate of AFP, TGF β1, Smad2, Smad2 mRNA , Smad4 and Smad4 mRNA in ANLT of HCC were respectively 52.1%(25/41), 95.1%(39/41), 56.1%(23/41), 82.9%(34/41), 78.0%(32/41), and 73.1%(30/41) . 4. The postive rates of TGFβ1, Smad4 and Smad2 mRNA in ANLT of HCC are higher than those of in HCC, however, The postive rates of AFP in ANLT of HCC are lower than those of in HCC.There were significant difference (P<0.05). 5. There were no obvious relationship between AFP, TGF β1 , Smad2 , Smad2 mRNA , Smad4 and age , sex , pathlogical grades (P>0.05); and so the same betweenSmad4 mRNA and age , sex. However , the expression of Smad4 mRNA was related to pathlogical grades (P<0.05). 6. There were no obvious relationship between TGFβ1 and AFP , Smad2 , Smad4 , Smad4 mRNA (P>0.05) .However , the expression of Smad2 mRNA was related to TGFβ1 (P<0.05). Conclusion 1. TGFβ1 is overexpression in HCC tissues . It's suggested that TGFβ1 is related to the formation of HCC, but not remarkably related to AFP. A autocrine and paracrine mechanism may be existed in tumor cell to produce TGFβ1 and it will promote proliferation, even metastasis. Both the expression of TGF-β1 and AFP are malignant phenotypes in HCC. The hepatocytes which surround the tumor can simultaneously express AFP and TGF-β1, are likely to be precancerous cells which have been initiated and possess the ability of neoplastic growth but lack phenotype transformation. 2. Smad2 is higher expressed in HCC tissues than that in normal liver tissues, which is so similar to that in hepatic cirrhosis. All of these, intensively sustain that hepatic cirrhosis and HCC are intimately correlated. 3. Smad4 is low expression in HCC tissues, loss of them will led to interruption of TGF pathway and induce HCC. Certainly, the expression of Smad4 mRNA is related to pathlogical grades, worse grade may be concomitant with less expression of Smad4 gene. 4. There are no relationship between TGFβ1 and Smad2 , Smad4 , Smad4 mRNA (P>0.05) .However , the expression of Smad2 mRNA is related to TGFβ1 (P<0.05). It indicates that many manners, whether Smad2, Smad4 dependent manner or Smad2, Smad4 independent manner, may in common complete the effect of TGFβ1. 5. It will be a new method to therapy HCC with genes if it is given Smad4mRNA , anti-TGFβ1 or anti-Smad2 , and so on.