Inhibitor of growth 4 induces apoptosis in human lung adenocarcinoma cell line A549 via Bcl-2 family proteins and mitochondria apoptosis pathway.
OBJECTIVE
Inhibitor of growth 4 (ING4) is considered to be a tumor suppressor implicated in several human malignancies by tumor growth inhibition and apoptosis enhancement. In present study, the effects of ING4 on apoptosis and its mechanisms were investigated through the transduction of ING4 cDNA into lung adenocarcinoma cell line A549.


METHODS
The effects of ING4 on A549 apoptosis were observed by FCM analysis, TUNEL assay, and electron microscopy. Simultaneously, the effects of ING4 on the expression of several apoptosis-related proteins in cell line A549 were evaluated by Western blot analysis.


RESULTS
Both Annexin-V FITC analysis by FCM and TUNEL assay revealed more apoptotic cells in A549 cells with exogenous ING4 gene. For electron microscopy, A549 cells with exogenous ING4 gene showed typical morphological changes of apoptosis. The deregulation of Bcl-2 family proteins (Bcl-2, Bcl-xl, Bax, Bak, Bid) and the major apoptotic executioners of mitochondria pathway (Cyt-c, caspase3, PARP) were also observed.


CONCLUSIONS
Our findings suggest that exogenous ING4 can enhance A549 apoptosis via regulating the expression of Bcl-2 family proteins and the activation of mitochondrial apoptotic pathway.
Li
Xiaomei
X
Department of Pathology, The Affiliated Tumor Hospital of Harbin Medical University, Harbin 150040, China.
Zhang
Qingyuan
Q
Cai
Limin
L
Wang
Yanhua
Y
Wang
Qian
Q
Huang
Xiaoyi
X
Fu
Songbin
S
Bai
Jing
J
Liu
Jinglei
J
Zhang
Guangmei
G
Qi
Jiping
J
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D005434:Flow Cytometry; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008168:Lung / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism*; D009368:Neoplasm Transplantation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D014183:Transplantation, Heterologous; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D018797:Cell Cycle Proteins; D018398:Homeodomain Proteins; C483230:ING4 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D025521:Tumor Suppressor Proteins; D045304:Cytochromes c; D053148:Caspase 3