Silencing profilin-1 inhibits gastric cancer progression via integrin β1/focal adhesion kinase pathway modulation.
OBJECTIVE
To investigate the role of profilin-1 (PFN1) in gastric cancer and the underlying mechanisms.


METHODS
Immunohistochemical analysis, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect PFN1 expression in clinical gastric carcinoma and adjacent tissues, and the association of PFN1 expression with patient clinicopathological characteristics was analyzed. PFN1 was knocked down to investigate the role of this protein in cell proliferation and metastasis in the SGC-7901 cell line. To explore the underlying mechanisms, the expression of integrin β1 and the activity of focal adhesion kinase (FAK) and the downstream proteins extracellular-regulated kinase (ERK)1/2, P38 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), AKT and mammalian target of rapamycin (mTOR) were measured through Western blot or qRT-PCR analysis. Fibronectin (FN), a ligand of integrin β1, was used to verify the correlation between alterations in the integrin β1/FAK pathway and changes in tumor cell aggressiveness upon PFN1 perturbation.


RESULTS
Immunohistochemical, Western blot and qRT-PCR analyses revealed that PFN1 expression was higher at both the protein and mRNA levels in gastric carcinoma tissues compared with the adjacent tissues. In addition, high PFN1 expression (53/75, 70.4%) was correlated with tumor infiltration, lymph node metastasis and TNM stage in gastric cancer, but not with gender, age, location, tumor size, or histological differentiation. In vitro experiments showed that PFN1 knockdown inhibited the proliferation of SGC-7901 cells through the induction G0/G1 arrest. Silencing PFN1 inhibited cell migration and invasion and down-regulated the expression of matrix metalloproteinase (MMP)-2 and MMP9. Moreover, silencing PFN1 reduced the expression of integrin β1 at the protein level and inhibited the activity of FAK, and the downstream effectors ERK1/2, P38MAPK, PI3K, AKT and mTOR. FN-promoted cell proliferation and metastasis via the integrin β1/FAK pathway was ameliorated by PFN1 silencing.


CONCLUSIONS
These findings suggest that PFN1 plays a critical role in gastric carcinoma progression, and these effects are likely mediated through the integrin β1/FAK pathway.
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Ya-Jun
YJ
Cheng
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Zhen-Xin
ZX
Zhu
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Jian-Sheng
JS
Zhou
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Zun-Qi
ZQ
Hu
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Jian-Peng
JP
Zhang
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Qing-Ping
QP
Cai
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Liang-Hua
LH
Wang
D002277:Carcinoma / Q000201:enzymology* / Q000235:genetics / Q000556:secondary; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D018450:Disease Progression; D005260:Female; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019012:Integrin beta1 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D051304:Profilins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D013997:Time Factors; D014162:Transfection
D019012:Integrin beta1; C495738:PFN1 protein, human; D051304:Profilins; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human
Fibronectin; Focal adhesion kinase; Gastric cancer; Integrin β1; Profilin-1