ABSTRACT
<p><b>BACKGROUND</b>To determine the inhibitory effect of antisense peptide nucleic acids (PNA) of telomerase on the growth of lung cancer cell lines.</p><p><b>METHODS</b>The synthesized modified antisense PNAs of telomerase were transfected into the lung cancer cell lines A549 and NCI-H446 respectively by lipofectamine transfection. Telomerase activity was detected by RT-PCR-ELLISA, and the cell counts were determined by MTT.</p><p><b>RESULTS</b>Seventy two hours after transfection with antisense PNAs of telomerase, telomerase activity (A450 value) of A549 and NCI-H446 were down regulated from 0.582 ±0.039, 0.571±0.043 to 0.294±0.048 ( P < 0.01), 0.276±0.051 ( P < 0.01) respectively, and alive cell counts (A580 value) of them from 0.485± 0.009 , 0.513±0.015 to 0.191±0.027 ( P < 0.01), 0.138±0.046 ( P < 0.01) respectively. The growth of two lung cancer cell lines were significantly inhibited.</p><p><b>CONCLUSIONS</b>Antisense PNA of telomerase might inhibit not only the telomerase activity, but also the growth of lung cancer cell lines in vitro.</p>
ABSTRACT
<p><b>BACKGROUND</b>To investigate the expression of the SOCS3 gene and its effect on proliferation of A549 cells.</p><p><b>METHODS</b>A549 cells were cotransfected with pEFSOCS3 and pSV2neo by liposome, then G418 was used to screen the positive cells. Expression of SOCS3 mRNA and protein was detected by RT-PCR and immunocytochemistry respectively before and after transfection. MTT assay was used to detect the cell growth. Flow cytometric DNA analysis was used to determine the cell cycle.</p><p><b>RESULTS</b>RT-PCR and immunocytochemistry showed that no expression of SOCS3 mRNA and protein was detected in A549 cells before transfection, but a stable expression of SOCS3 gene was observed after transfection with SOCS3 gene. Compared with control group, growth of A549 cells transfected with SOCS3 gene was significantly suppressed, with a suppressive rate of 41.07%. The cells at G₀/G₁ cell phases increased, and those at S and G₂/M phases decreased significantly after transfection.</p><p><b>CONCLUSIONS</b>SOCS3 protein might inhibit the proliferation of A549 cells by negatively regulating cellular signal pathways.</p>
ABSTRACT
<p><b>BACKGROUND</b>To evaluate the clinical significance of telomerase activity in lung cancer and to investigate the possibility of telomerase as cancer marker for lung cancer.</p><p><b>METHODS</b>The activity of telomerase was investigated by TRAP-PCR-ELISA in lung cancer tissues and corresponding adjacent noncancerous tissues obtained from resected specimens of 48 patients with lung cancer and 42 specimens of benign pulmonary lesions were examined simultaneously.</p><p><b>RESULTS</b>Telomerase activity was detected in 42 (87.5%) of the 48 tumors and only 4 (8.3%) of the 48 adjacent noncancerous lung tissue samples (Chi-Square=13.029, P < 0.01), but in none of 42 specimens of benign pulmonary lesions (Chi-Square=14.016, P < 0.01). Correlation with pathological parameters showed that the expression of telomerase activity was associated with lymph node metastasis (93.5% vs 76.4% , Chi-Square=63.511, P < 0.01), but not with histological type, location and differenciated grade of tumor.</p><p><b>CONCLUSIONS</b>Telomerase activation correlates with the carcinogenesis and aggressiveness of lung cancer. Telomerase might be one of the important diagnostic and prognostic factors in patients with lung cancer.</p>
ABSTRACT
Objective To investigate the variations of mtDNA from high and low metastatic mouse hepatocarcinoma cell sublines Hca-F and Hca-P, and the relationship between mutations of mtDNA and carcinogenesis. Methods The variations of D-loop, ND3 and tRNA Met+Glu+Ile gene fragments of mtDNA from Hca-F and Hca-P cells were analyzed by PCR-RFLP and sequencing techniques. Results No amplification fragment length polymorphism and restriction fragment length polymorphism were observed in tRNA Met+Glu+Ile , ND3 and D-loop of mtDNA from the 2 cell sublines. Sequence difference between these 2 cell sublines were found in mtDNA D-loop region by sequencing. Conclusions Genetic alteration of mtDNA non-coding region in tumors, which may reflect the environmental and genetic influences operative during tumor progression, can be linked to their tumorigenic phenotype.
ABSTRACT
Objective To study the 4 977 bp deletion of mitochondrial DNA in lung cancer, paraneoplastic tissue and normal lung tissue from non-lung cancer subjects and its significance in the development of cancer. Methods Lung cancer tissues and paraneoplastic tissues from 37 non-small lung cancer patients, and normal lung tissues from 20 patients without lung cancer were analyzed by long PCR technique. Results Mitochondrial DNA 4 977 bp deletion was detected in 54.1%(20/37) of lung cancer tissues, 59.5%(22/37) of paraneoplastic tissues and 30.0%(6/30) of normal lung tissues. The correlation between 4 977 bp deletion and age, smoking was present in our data. Conclusion Mitochondrial DNA 4 977 bp deletion, which may reflect the environmental and genetic influences during tumor progression, is not specific to lung cancer and unlikely to play an important role in carcinogenesis.