[Down-regulation of CT120A by RNA interference suppresses lung cancer cells growth].
OBJECTIVE
To validate our obtained outcomes and clarify the relationship between CT120A, a novel human plasma membrane-associated gene, and proliferation of lung cancer cells.


METHODS
A vector-based small hairpin RNA (shRNA) was transfected into the human lung adenocarcinoma SPC-A-1 cells to specifically target CT120A cDNA. RT-PCR and Western blotting were used to analyze the CT120A expression. The cell proliferation rate was analyzed by BrdU-TdR incorporation assay, the ability of cells to grow in soft agarose and the tumorigenicity in nude mice were measured. Flow cytometry was performed to analyze cell apoptosis.


RESULTS
When compared with the scrambled control cell line, CT120A transcripts were reduced by 70% and 50% in two shRNA-H stable transfectants, H2 and H3 clones, respectively. The protein of CT120A was reduced by about 80% in both the H2 and H3 clones. By BrdU incorporation assay, up to the 6th day a dramatic decrease in the cell growth rate (30% to 40%) was observed in the shRNA-H2 and shRNA-H3 cell lines. The colony formation rate in soft agarose of the two cell lines was about one half that of the control cells. In addition, a remarkable reduction of tumorigenicity of the two cell lines was observed as compared with that of the control. The suppression of CT120A expression also sensitized cells to ultraviolet-induced apoptosis.


CONCLUSIONS
Down-regulation of CT120A by RNA interference suppresses lung cancer cell growth. The successful knockdown of CT120A expression by RNA interference implicates that CT120A may be a new candidate of drug target for treatment of lung cancers.
Pan
Dong-ning
DN
National Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai 200032, China.
Wei
Lin
L
Yao
Ming
M
Wan
Da-fang
DF
Gu
Jian-ren
JR
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000818:Animals; D002455:Cell Division; D045744:Cell Line, Tumor; D015536:Down-Regulation; D020868:Gene Silencing; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D034622:RNA Interference / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D014407:Tumor Cells, Cultured
D008565:Membrane Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; C467481:TLCD3A protein, human