[Effect of p73 gene on chemosensitivity of human lung adenocarcinoma cells H1299].
OBJECTIVE
Recent studies have shown that wild-type p53 gene can enhance the chemosensitivity of the majority of non-small cell lung cancers. p73 gene and its homologue p53 gene have significant sequence and functional similarities. This study was designed to investigate the effect of p73 gene on chemosensitivity of human lung adenocarcinoma cells H1299.


METHODS
The pcDNA3-HA-p73alpha plasmid were transferred into in vitro cultured human lung adenocarcinoma cell line H1299 with Dosper. The p73alpha positive cells which were resistant to G418 were selected out. The expression of exogenous P73alpha protein were examined by Western blot analysis. MTT assay were used to analyze the response of transfected cells to cisplatin (cDDP),adriamycin (ADM). The drug-induced apoptosis of transfected cells was measured by flow cytometry and TUNEL technique. The biological behavior changes of the cells were observed by colony formation assay.


RESULTS
The transfected lung adenocarcinoma cell line H1299 overexpressed P73alpha protein stably. MTT assay showed that the IC(50) values for cDDP and ADM were reduced to approximate 86.2% and 99.2% in the transfected cells compared with the untransfected cells, respectively. The low concentration of chemotherapeutic drugs (1.25 micromol/L cDDP or 0.05 micromol/L ADM) without inhibition essentially suppressed the growth of the transfected cells markedly. The cDDP-induced apoptosis rate increased from 10.1% to 38.4%(P< 0.01). The ADM-induced apoptosis rate increased from 12.1% to 49.3%(P< 0.01). Colony-formation assays showed that the colony number in transfected cells was decreased significantly by chemotherapeutic drugs compared with parental cells(P< 0.01). The sensitive enhancement ratios for cDDP or ADM were 1.8 and 2.6, respectively.


CONCLUSIONS
p73 gene was capable of enhancing the sensitivity of H1299 cells to chemotherapeutic drugs such as cDDP and ADM, and the increased sensitivity was associated with the induction of apoptosis undepend p53 gene. It suggests the possibility of using p73 gene combined with anticancer agents to improve the effectiveness of chemotherapy.
He
Yong
Y
Thoracic Surgery Center of People's Liberation Army, The Third Military Medical University, Chongqing, PR China.
Fan
Shi-Zhi
SZ
Jiang
Yao-Guang
YG
Chen
Jian-Ming
JM
Li
Zhi-Ping
ZP
Zhou
Ping
P
Zhou
Yuan-Guo
YG
D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D016147:Genes, Tumor Suppressor; D006801:Humans; D020128:Inhibitory Concentration 50; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins
D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D004317:Doxorubicin; D002945:Cisplatin