Influence of the hTERT rs2736100 polymorphism on telomere length in gastric cancer

Figure 1 Genotypes of rs2736100 by polymerase chain reaction-restriction fragment length polymorphism. SfcI restriction enzyme recognizes and cuts the polymerase chain reaction (PCR) product of C-type allele. Lane M: 50 base pair ladder; Lane 1 and 2: SfcI digested PCR product is homozygous (A/A); Lane 3: SfcI digested PCR product is homozygous (C/C); Lane 4 and 5: SfcI digested PCR product is heterozygous (C/A).

Figure 2 Association of the rs2736100 polymorphism with hTERT mRNA expression in 5 gastric cancer cell lines. A: The genotype of rs2736100 polymorphism of the hTERT gene was determined by polymerase chain reaction-restriction fragment length polymorphism. The genotype of AGS and MKN1 cells was C/C homozygote, MKN45 and SNU-638 was heterozygote, and KATO-III was A/A homozygote. GKN1 treatment significantly reduced the expression of hTERT gene in 5 gastric cancer cell lines (^aP < 0.05); B: The genotype of rs2736100 polymorphism of the hTERT gene was closely associated with hTERT mRNA expression in non-treated gastric cancer cells; C: Fold changes of hTERT mRNA expression in GKN1-treated compared to non-treated gastric cancer cells were assessed by real time QPCR. GKN1 treatment markedly down-regulated hTERT mRNA expression, especially in MKN-45 and SNU-638 cells with C/A heterozygote and KATO-III cell with A/A homozygote. hTERT: Human telomerase reverse transcriptase.

Figure 3 Association of the rs2736100 polymorphism with hTERT mRNA expression and telomere length in 35 gastric cancers. A: The genotype of rs2736100 polymorphism of the hTERT gene was closely associated with hTERT mRNA expression and telomere length (P = 0.0026 and P = 0.0199, respectively); B: When we combined C/A and A/A genotypes, the cases carrying the A allele (A/A and C/A genotypes) showed lower hTERT mRNA expression levels and shortened telomere length, compared with those who had C/C homozygote genotype (P = 0.0016 and P = 0.0098, respectively). hTERT: Human telomerase reverse transcriptase.

Figure 4 Association of the rs2736100 polymorphism with hTERT mRNA expression and telomere length in intestinal- and diffuse-type gastric cancers. A: The telomere length shortened in diffuse-type gastric cancer (P = 0.0251), but hTERT mRNA expression was not associated with histologic differentiation of gastric cancers (P = 0.1485); B: When we combined C/A and A/A genotypes, telomere length and hTERT mRNA levels were markedly increased in those with the C/C genotype in intestinal-type gastric cancer (P = 0.0069 and P = 0.0204, respectively); C: The rs2736100 polymorphism was not associated with hTERT expression and telomere length in diffuse-type gastric cancers (P = 0.1414 and P = 0.2298, respectively). hTERT: Human telomerase reverse transcriptase; INT: Intestinal-type gastric cancer, DIF: Diffuse-type gastric cancer.