Ectopic expression of guanylyl cyclase C in gastric cancer as a potential biomarker and therapeutic target.
OBJECTIVE
To investigate the expression of guanylyl cyclase C (GCC) in human gastric cancer (GC) tissues and assess the effect of GCC small interfering RNA (siRNA) on the proliferation and apoptosis of SGC-7901.


METHODS
The expression of GCC in 30 specimens and three human GC cell lines (SGC-7901, AGS, NCI-N87) were detected by RT-PCR for messenger RNA (mRNA) by Western blot and immunofluorescence for proteins. Recombinant plasmids containing GCC siRNA and scrambled siRNA were constructed and transfected into SGC-7901 cells, respectively. A cell counting kit-8, flow cytometry (FCM) and terminal deoxynucleotidyl transferase (TDT)-mediated dUTP-biotin nick end-labeling were used to evaluate cell viability, cell cycle distribution and apoptosis, followed by wound healing assay and cell adherent assay for cell motility and adherent, respectively.


RESULTS
The expression of GCC was absent in paracancerous tissues, whereas the GCC mRNA and protein expressions were detected in 20/30 and 19/30 of GC specimens, respectively. Moreover, intestinal GC was statistically different from diffuse GC (P < 0.05). The proliferation of SGC-7901 cells was markedly inhibited by GCC siRNA-3 (P < 0.05) and cell morphological changes including volumetric reduction, karyopyknosis and karyorrhexis were observed. FCM showed that the cell count in the sub-G0/G1 peak increased from 5.47% (48 h after transfection) to 5.63% (72 h after transfection). The wound healing assay and cell adherent assay revealed that GCC gene silencing decreased cell motility and adherent.


CONCLUSIONS
The over-expression of GCC has been detected in intestinal type GC. GCC siRNA can effectively inhibit the proliferation and invasion of SGC-7901 cells and induce cell apoptosis. GCC might be a novel biomarker and therapeutic target for GC.
Mao
Zhen Biao
ZB
Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, China. mzb63@163.com
Zhang
Jian Feng
JF
Xu
Zhong
Z
Zhu
Hui Jun
HJ
Zhang
Jian Guo
JG
Pan
Zheng Ping
ZP
Xiao
Feng
F
Yang
Jun Ling
JL
D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D000071616:CDX2 Transcription Factor; D002448:Cell Adhesion; D002455:Cell Division; D045744:Cell Line, Tumor; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D015316:Genetic Therapy / Q000379:methods*; D006162:Guanylate Cyclase / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D011230:Precancerous Conditions / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D014162:Transfection
D014408:Biomarkers, Tumor; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018000:Receptors, Peptide; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled