Association analysis of FAS-670A/G and FASL-844C/T polymorphisms with risk of generalized aggressive periodontitis disease

The interaction of FAS/FAS ligand (FASL) serves an important role in the upregulation of apoptotic processes through different mechanisms in cells. Previous studies have established that the polymorphisms FAS-670A/G and FASL-844C/T are associated with risk of generalized aggressive periodontitis (GAP) in different ethnic populations. Therefore, in the present study, it was investigated for the first time whether FAS-670A/G and FASL-844C/T polymorphisms were associated with risk of GAP in Iran. This case-control study performed the polymerase chain reaction-restriction fragment length polymorphism method in 25 patients with GAP and 110 normal subjects as controls. The results indicated that there was no significant difference in FAS-670A/G genotype frequency between the GAP and control groups. A higher frequency of the combined genotype (AG+GG) was observed in the GAP patients (96.0%) compared with the control subjects (90.9%), though this was not significant [χ²=0.705, degrees of freedom (df)=1, P=0.401]. Similarly, the prevalence of the G allele was non-significantly higher in the GAP group (62.0%) compared with that in the controls (60.0%; χ²=0.012, df=1, P=0.913). For FASL-844C/T polymorphism, the frequency of the combined genotype (CT+TT) was higher in the GAP group (96.0%) when compared with the control subjects (91.8%); however its association was not statistically significant (χ²=0.519, df=1, P=0.471). The frequency of the T allele only marginally differed between the groups, being 60.0% in the GAP group and 50.9% in the controls (χ²=3.627, df=1, P=0.057). These results indicated that there were no significant associations between the FAS-670A/G and FASL-844C/T polymorphisms and the risk of disease in GAP patients when compared with normal individuals.

Mechanism of apoptosis induction associated with ERK1/2 upregulation via goniothalamin in melanoma cells

The present study aimed to investigate the effect of goniothalamin on apoptosis induction in the A375 melanoma cell line. Melanoma is a type of skin cancer with increased prevalence and no potential standard treatment. Goniothalamin is a plant, bioactive styrly-lactone, which has various bioactivities including anti-microbial, anti-inflammatory and anti-cancer. Apoptosis induction by goniothalamin has been studied in numerous cancer cell lines, however not in the melanoma cell line A375. The results of the MTT assay demonstrated that goniothalamin induced anti-proliferation in a dose dependent manner. Hoechst staining assay demonstrated that goniothalamin induced chromatin condensation and apoptotic bodies in A375 treated cells, and JC-1 staining revealed that goniothalamin induced mitochondrial membrane dysfunction in A375 cells. In addition, goniothalamin decreased the level of anti-apoptotic proteins myeloid cell leukemia 1, B cell lymphoma (Bcl)-2 and Bcl-extra large, whereas it increased the level of pro-apoptotic proteins, Bcl-2 Associated X, apoptosis regulator, t-BID and Bim in A375 treated cells. In addition, goniothalamin also increased active caspase-9, -7 and cleaved-poly (ADP-ribose) polymerase expression in A375 treated cells. Furthermore, phosphorylated (p)-pyruvate dehydrogenase kinase (PDK) 1 (Ser241) and p-RAC-alpha serine/threonine-protein kinase (Akt; Ser473) were decreased, however c-Jun and p-extracellular signal-regulated kinase (ERK)1/2 were increased upon goniothalamin treatment. These results suggest that goniothalamin has an effect, as anti-proliferation and apoptosis induction in A375 cells were associated with upregulated p-ERK1/2, c-Jun and downregulated p-PDK1 (Ser241), p-Akt (Ser473) in A375 cells. Therefore, goniothalamin may be a potential candidate for anti-cancer drug development for melanoma treatment.

FASL -844C polymorphism is associated with increased activation-induced T cell death and risk of cervical cancer

The FAS receptor-ligand system plays a key role in regulating apoptotic cell death, and corruption of this signaling pathway has been shown to participate in tumor-immune escape and carcinogenesis. We have recently demonstrated (Sun, T., X. Miao, X. Zhang, W. Tan, P. Xiong, and D. Lin. 2004. J. Natl. Cancer Inst. 96:1030-1036; Zhang, X., X. Miao, T. Sun, W. Tan, S. Qu, P. Xiong, Y. Zhou, and D. Lin. 2005. J. Med. Genet. 42:479-484) that functional polymorphisms in FAS and FAS ligand (FASL) are associated with susceptibility to lung cancer and esophageal cancer; however, the mechanisms underlying this association have not been elucidated. We show that the FAS -1377G, FAS -670A, and FASL -844T variants are expressed more highly on ex vivo-stimulated T cells than the FAS -1377A, FAS -670G, and FASL -844C variants. Moreover, activation-induced cell death (AICD) of T cells carrying the FASL -844C allele was increased. We also found a threefold increased risk of cervical cancer among subjects with the FASL -844CC genotype compared with those with the -844TT genotype in a case-control study in Chinese women. Together, these observations suggest that genetic polymorphisms in the FAS-FASL pathway confer host susceptibility to cervical cancers, which might be caused by immune escape of tumor cells because of enhanced AICD of tumor-specific T cells.