Expression analysis of apoptosis-related genes BCL2L12 and PDCD4 in patients with leukemia

A30

Apoptotic cell death is a highly regulated process, which plays a crucial role in many biological events.The apoptosis-related gene BCL2L12 is located on 19q13.3-13.4 and encodes the BCL2L12 protein which is effective during apoptosis like other Bcl-2 family proteins.The other apoptosis-related gene Pdcd4 is located on 10q24 and encodes the Pdcd4 protein. PDCD4 is a tumor suppressor gene that is overexpressed during apoptosis. Hematologic cancers arise from the stem cells in hematopoetic organs. Chronic myeloid leukemia is a disease mostly seen in adults with rate of 15-20% in overall cancers. Although there is evidence that the BCL2L12 protein is effective on apoptotic pathways, the data with regard to whether it exerts a pro-apoptotic or anti-apoptotic effect are controversial.
 In our study, we investigated in the difference expression of BCL2L12 and PDCD4 genes in patients with CML. 57 CML patients and 50 healthy control subjects were involved in the study.
 BCL2L12 and PDCD4 gene expression were investigated by RT-PCR. RNA was extracted from peripheral blood lymphocytes using the High Pure RNA Isolation Kit (Roche), following the manufacturer’s instructions and stored at -80⁰C prior to cDNA synthesis. RNA concentration was determined spectrophotometrically. 2.5 µg of total RNA were reverse-transcripted into the cDNA using the Transcriptor First Strand cDNA Synthesis Kit (Roche). Spesific primers for the actin, BCL2L12 and PDCD4 genes were used and PCR was carried out for 35 cycles. Equal amounts of PCR products were electrophoresed on 2% agarose gels and visualised by ethidium bromide staining. The actin gene was used as an internal control for the integrity of the mRNA.
 From the 57 CML patients examined, 34 (60%) were classified positive for expression of the BCL2L12 gene and 31 (54%) were classified positive for PDCD4 overexpression. On the other hand, among the 50 healthy subjects, 42 (84%) were positive for BCL2L12 gene expression and 35 (70%) were positive for overexpression of the PDCD4 gene. The associations between the gene expression and clinical variables, including age, sex, Bcr-Abl translocation and survival rate have been compared. No significant assosiations were found between the BCL2L12 gene expression or PDCD4 gene overexpression and clinical variables.
 We found that the number of people who express BCL2L12 in the control group was approximately 5 times higher than the number of the people in the patients group (p=0.06). On the other hand, PDCD4 expression frequency was approximately 3 times higher in the patiens group ( p=0.011).